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23144 Gender Ratio gender-ratio page publish <!-- wp:html --> <div class="blog-info">This article was first published in June 2019.</div> <!-- /wp:html --> <!-- wp:paragraph --> <p>The ratio between the number of males and females in a society is referred to as the gender ratio. This ratio is not stable but instead shaped by biological, social, technological, cultural, and economic forces. And in turn the gender ratio itself has an impact on society, demography, and the economy.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In this entry we provide an overview of the variation and the changes of the gender ratio across the world. We study how it changes from birth to late life; the forces that change the ratio of men to women.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Many argue persuasively that the terms 'gender' and 'sex' are not to be used interchangeably.{ref}Pryzgoda, J., &amp; Chrisler, J. C. (2000). Definitions of gender and sex: The subtleties of meaning.&nbsp;<em>Sex Roles</em>,&nbsp;<em>43</em>(7-8), 553-569.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p> In this context here we have however decided to make an exception: we speak of the 'gender ratio' because it's the established term and it will help all those who want to be informed about this topic and search this term. But we also speak of the 'sex ratio' because this is arguably the more accurate term and it is increasingly used within the academic literature.</p> <!-- /wp:paragraph --> <!-- wp:owid/summary --> <!-- wp:list --> <ul><li><a href="https://ourworldindata.org/gender-ratio#sex-ratio-at-birth">The sex ratio at birth is not equal: in every country births are male-biased. There are biological reasons why there are slightly more boys born every year than girls. The 'natural' sex ratio at birth is around 105 boys per 100 girls (ranging from around 103 to 107 boys).</a></li><li><a href="https://ourworldindata.org/gender-ratio#biology-or-discrimination-which-countries-have-skewed-sex-ratios-at-birth">In some countries, the sex ratio at birth is much more skewed than would occur naturally. Today and in the recent past this is particularly common across Asia and North Africa. Here there is clear evidence of gender selection through prenatal sex determination and selective abortion.</a></li><li><a href="https://ourworldindata.org/gender-ratio#how-does-sex-ratio-vary-with-birth-order">In countries where there is a clear son preference, the sex ratio at birth becomes increasingly skewed with birth order (the third or fourth born children are more likely to be boys than the first or second child).</a></li><li><a href="https://ourworldindata.org/gender-ratio#sex-ratio-in-childhood">In nearly every country, boys are more likely to die in childhood than girls. There are biological reasons for this: boys are more susceptible to birth complications and infectious diseases.</a></li><li><a href="https://ourworldindata.org/gender-ratio#infanticide-and-excess-female-mortality">In countries where there is strong son preference, mortality rates for girls are higher than would be expected: this can occur either through direct infanticide, but also through neglect and unequal treatment.</a></li><li><a href="https://ourworldindata.org/gender-ratio#sex-ratio-through-adulthood">The sex ratio tends to decrease&nbsp;over the life course (from becoming male-biased to female-biased). This is because women tend to live longer than men.</a></li><li><a href="https://ourworldindata.org/gender-ratio#how-many-missing-women-are-there">It's estimated that today there are over 130 million 'missing women' in the world as a result of selective abortion and excess female deaths.</a></li><li><a href="https://ourworldindata.org/gender-ratio#does-banning-prenatal-practices-reduce-sex-selective-abortion">The banning of sex determination scanning and gender-selective abortion may have limited the increase in sex ratio at birth in some countries, but did not fully address the problem.</a></li><li><a href="https://ourworldindata.org/gender-ratio#do-richer-and-more-educated-parents-have-less-gender-bias">Development can have opposing impacts on sex ratio: there is evidence that the son preference declines with education, but this often goes hand-in-hand with declining fertility rates and increased access to selective technologies (which can increase the sex ratio).</a></li></ul> <!-- /wp:list --> <!-- /wp:owid/summary --> <!-- wp:heading --> <h2>Gender Ratio across the world</h2> <!-- /wp:heading --> <!-- wp:heading {"level":3} --> <h3>What share of the population is male and female?</h3> <!-- /wp:heading --> <!-- wp:paragraph --> <p>The sex ratio – the share of the population that is female – varies across the world. And globally in 2020 the share of women in the world was just under 50%.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>There are three reasons why the sex ratio of populations varies and is rarely equal:</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li>differences in mortality rates and life expectancy for women and men. Women, on average, <a href="https://owid.cloud/why-do-women-live-longer-than-men">live longer than men</a>. This means that all else being equal, we would expect females to account for slightly more than half of the total population.</li><li>sex ratios at birth are not equal. In all countries, there are more male than female births (the extent of which varies by country as we will see below). This means that all else being equal, we would expect males to account for slightly more than half of the total population.</li><li>migration can also affect the sex ratio of the population. If in some countries there is a significant amount of imported male-dominant labour, all else being equal, we would expect males to account for more than half of the total population.</li></ul> <!-- /wp:list --> <!-- wp:paragraph --> <p>The magnitude and balance of these factors determines the sex ratio of the total population.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the map we see the sex ratio of populations: this is shown as the percentage of the total population which is female. Countries over 50 percent (shown in blue) have more females than males; those below 50 percent (shown in red) have fewer females.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Most countries have a female share of the population between 49 and 51 percent (within one percentage point of parity).</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>There are however a few notable outliers:</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li>across several countries in South and East Asia – most notably India and China – there are significantly fewer females than males. These are countries where there are large differences in sex ratio at birth.</li><li>in several countries across the Middle East there are many more males than females: in Oman, women are outnumbered 3-to-1; in the United Arab Emirates (UAE) it's almost 4-to-1. If we look at how this has changed over time (click on the country to see this), we see the share of the population that is female has declined from a ratio close to parity decades ago. The primary reason for this is a large male migrant stock: in 2017, 45 percent of the Oman and 88 percent of the UAE population were from immigration.{ref}United Nations, Department of Economic and Social Affairs, Population Division (2017). <a href="http://www.un.org/en/development/desa/population/migration/publications/migrationreport/docs/MigrationReport2017_Highlights.pdf">International Migration Report 2017</a>&nbsp;(ST/ESA/SER.A/403).{/ref} The UN reports that only 16 and 25 percent of international migrants to Oman and UAE, respectively, were female. </li><li>there are significantly more females than males in Eastern Europe. Populations in Eastern Europe have some of the largest gaps in life expectancy between men and women: in Russia in 2021, for example, the life expectancy at birth for men was only around 64 years compared to around 75 years for women.</li></ul> <!-- /wp:list --> <!-- wp:html --> <iframe style="width: 100%; height: 600px; border: 0px none;" src="https://ourworldindata.org/grapher/share-population-female"></iframe> <!-- /wp:html --> <!-- wp:heading --> <h2>Gender Ratio at birth and through the life course</h2> <!-- /wp:heading --> <!-- wp:heading {"level":3} --> <h3>How does the sex ratio at birth vary across the world?</h3> <!-- /wp:heading --> <!-- wp-block-tombstone 26470 --> <!-- wp:paragraph --> <p>Across the world there are differences in the sex ratio at different life stages. This imbalance in the male and female population can in some cases be traced back to birth: in some countries the number of boys and girls born each year is significantly skewed.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the map we see the differences in sex ratio at birth across the world. Here the sex ratio is measured as the number of male births for every 100 female births; a value greater than 100 indicates there are more boys than girls born that year. A figure of 110 would indicate that there are 110 male births for every 100 female births.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The first striking point is that in every single country of the world there are more boys born than girls. This has been true for all years for which we have data (as far back as 1950) in all countries of the world, as you can when you move the timeslider below the map further back.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Does this mean every country selects for boys prior to birth; for example, through induced abortion practices which preferentially select for boys? Not necessarily.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the absence of selective abortion practices, births in a given population are typically male-biased – the chances of having a boy are very slightly higher than having a girl.</p> <!-- /wp:paragraph --> <!-- wp:html --> <figure><iframe src="https://ourworldindata.org/grapher/sex-ratio-at-birth"></iframe></figure> <!-- /wp:html --> <!-- wp:heading {"level":4} --> <h4>Why are births naturally expected to be male-biased?</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>For most countries, there are around 105 males per 100 female births. This is what the World Health Organization (WHO) estimates as&nbsp;the <a href="https://ourworldindata.org/gender-ratio#definitions">'expected' sex ratio</a> at birth: in the absence of gender discrimination or interference we'd expect there to be around 105 boys born per 100 girls, although this can range from around 103 to 107 boys per 100 girls.&nbsp;Why is this?</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the most comprehensive study of its kind, Orzack et al. (2015) monitored the trajectory of sex ratio from conception through to birth across five different methods.{ref}Orzack, S. H., Stubblefield, J. W., Akmaev, V. R., Colls, P., Munné, S., Scholl, T., … &amp; Zuckerman, J. E. (2015). <a href="https://pdfs.semanticscholar.org/3986/f62b66ee8450859909e122fb2974c1c9fe6b.pdf">The human sex ratio from conception to birth</a>. <em>Proceedings of the National Academy of Sciences</em>, 112(16), E2102-E2111.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p> This produced the largest dataset available on the sex ratio throughout the stages of pregnancy.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>A key result from this study was that the sex ratio at conception is equal: there is no difference in the number of males and females conceived. For births to be consistently male-biased, there must be gender differences in the probability of miscarriage through pregnancy.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The study found that although the probability of miscarriage varies between genders across the course of a pregnancy, female mortality is slightly higher than male mortality over the full period:</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li>there is a higher probability that an embryo with chromosomal abnormalities{ref}In the paper the authors differentiate between 'karyotypically normal' and 'karyotypically abnormal'. This refers to whether there are mutations in chromosomes, such as an extra, missing or irregular portion of chromosomal DNA. 'karyotypically abnormal' embryos have a lower probability of surviving to birth, or often lead to other human diseases/conditions.{/ref} is male – in the first week of pregnancy, excess male mortality therefore means pregnancy is female-biased;</li><li>in the next 10-15 weeks of pregnancy female mortality is higher, which increases the ratio in favor of males;</li><li>male and female mortality is approximately equal around week 20;</li><li>between weeks 28-35 of pregnancy, there is higher male mortality.</li></ul> <!-- /wp:list --> <!-- wp:paragraph --> <p>Overall, a male-biased sex ratio at birth is the result.</p> <!-- /wp:paragraph --> <!-- wp:heading {"level":4} --> <h4>In some countries the sex ratio is skewed beyond the expected sex ratio</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Some male-bias in births is what we expect with no deliberate gender selection through parents or society more broadly. There are, however, some key outliers in the world today: in countries including China, India, Vietnam, Pakistan, and Azerbaijan this ratio is very skewed. Here it's likely that deliberate selection practices explain part of the high sex ratio as we explore <strong><a href="https://ourworldindata.org/gender-ratio#biology-or-discrimination-which-countries-have-skewed-sex-ratios-at-birth">here</a></strong>.</p> <!-- /wp:paragraph --> <!-- wp:heading {"level":3} --> <h3>The sex ratio varies with birth order</h3> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Most countries have a <a href="https://ourworldindata.org/gender-ratio#sex-ratio-at-birth">sex ratio at birth</a> which is around the <a href="https://ourworldindata.org/gender-ratio#definitions">expected range of 105 boys born for every 100 girls</a>.&nbsp;There are exceptions to this: there are countries – most notably in Asia – with highly skewed sex ratios in favor of males.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The preference in some countries for a son is seen in the overall sex ratio at birth figures above. But this bias is even stronger when we look at how this ratio is affected by the birth order of children.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In this visualization we look at the case of India and how sex ratios change from the 1st child in a family through to the 2nd, 3rd, 4th, and 5th born children. This is adapted from the&nbsp;<em>Economic Survey 2018</em>{ref}Jaitley, A. (2018). <em><a href="https://ideas.repec.org/p/ess/wpaper/id12445.html">Economic Survey 2017-18: Volume I, Chapter 7: Gender and Son Meta-Preference: Is Development Itself an Antidote?</a></em>{/ref} and based on data from the DHS and National Family Health Surveys in India. It presents this data in two cases:</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li>when the child <em>is not</em> the last child born (i.e. the parents have additional children afterwards) – this is shown in the charts on the left;</li><li>when the child <em>is</em> the last child born in the family (i.e. the parents stop having children afterwards) – this is shown on the right.</li></ul> <!-- /wp:list --> <!-- wp:paragraph --> <p>Let's first focus on the top row, which presents the data for India as a whole. On the left-hand side we have the sex ratio at birth when the child <em>is not</em> the last. For the 1st children, the sex ratio is very close to what we would expect 'naturally': a ratio of around 105 boys per 100 girls. But we see that for the 2nd, 3rd, 4th and 5th born children, this ratio is skewed towards girls. Remember again that this is the case when it's not the last child i.e. the parents go on to have another. In other words this shows us that when a girl is born, parents are more likely to have another child. It is evidence that parents are continuing to have children until they get a son.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Compare this to the right-hand side where we see the sex ratio when the child <em>is</em> the last. These ratios are much more skewed towards boys. Parents whose 1st child is a son are much more likely to stop having children. The sex ratio here is 182 boys per 100 girls. This is consistent across the birth order: whether it's the 2nd, 3rd, 4th or 5th child, a family is much more likely to stop having children when they have a boy.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Combined we see a strong preference for a son in India: parents are more likely to continue having more children when the child is a girl and they are more likely to stop having children when they have a boy.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Now compare these ratios to that of Indonesia in the second row below. Sex ratios here do not diverge strongly from the expected ratio of 105, and there is no clear difference when the child is or isn't the last to be born.&nbsp;Parental choices do not point to a strong preference for a son or a daughter.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the third row we see that within India there are large differences in son preference across different states. The data shows that there are states with 'weaker' and 'stronger' preference for a son.</p> <!-- /wp:paragraph --> <!-- wp:image {"align":"center","id":23711,"linkDestination":"custom"} --> <div class="wp-block-image"><figure class="aligncenter"><a href="https://owid.cloud/app/uploads/2019/06/Sex-ratio-at-birth-by-order.png"><img src="https://owid.cloud/app/uploads/2019/06/Sex-ratio-at-birth-by-order-438x550.png" alt="" class="wp-image-23711"/></a></figure></div> <!-- /wp:image --> <!-- wp:heading {"level":4} --> <h4>Sex selection practices also became more prominent for later births</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>From the study presented above we see that the sex of a child can, in some countries, be an important deciding factor for when parents stop having children.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>But birth order also influences the likelihood of prenatal sex selection (PSS) i.e. sex-selective abortion. We see evidence of this across several countries.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Researchers looked at Indian national survey data from 1976 to 2005 to see how the sex of children and birth order affects the use of prenatal selection.{ref}Gellatly, C., &amp; Petrie, M. (2017). <a href="https://jech.bmj.com/content/71/3/269">Prenatal sex selection and female infant mortality are more common in India after firstborn and second-born daughters</a>. <em>Journal of Epidemiology &amp; Community Health</em>, 71(3), 269-274.{/ref} They found a significant and increasing skew in the sex ratio since the 1980s – a time when the <a href="https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=IND">average woman in India had five children</a>. This was mainly a result of male selection for the 2nd or 3rd child within a family.&nbsp;When the firstborn or the first- and second-born siblings were female then a boy was much more likely the 2nd or 3rd child. This skewed ratio can only be explained from prenatal sex selection in favor of boys.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>At a local level, a study of a large Delhi hospital known for maternal care showed very similar results.{ref}Manchanda, S., Saikia, B., Gupta, N., Chowdhary, S., &amp; Puliyel, J. M. (2011). <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0020097">Sex ratio at birth in India, its relation to birth order, sex of previous children and use of indigenous medicine</a>. <em>PLoS One</em>, 6(6), e20097. {/ref} The overall sex ratio was male-biased with only 806 girls per 1000 boys. But this got significantly worse when the family already had a daughter: 720 girls per 1000 boys if there was one previous girl and only 178 girls per 1000 boys for two previous daughters. Even for women who had not practiced sex-selection abortion, more mothers who had previously had a girl reported taking traditional medicines (which were ineffective) for sex selection purposes.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>These examples are of course not restricted to India. Many countries across Asia in particular have similar findings. In this chart we see how the sex ratio in South Korea was affected by birth order. Here we see a very steep rise in the sex ratio of third-, fourth- and later children through the 1980s. By the early 1990s there were more than 200 boys per 100 girls for third-born children; for fourth-born or higher, the ratio was close to 250:100. This occurred at a time the <a href="https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=KOR">number of children per woman was falling quickly</a>: in 1970 its fertility rate was 4.3 children per woman; by 1990 this had fallen to 1.6. South Korea's sex ratio has fallen back to close to natural levels over the past few decades.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>You can also view the data for China, by using the "change country" button in the top-left of the chart. Clearly sex ratios in China have also been affected by birth order.{ref}Jiang, Q., Yu, Q., Yang, S., &amp; Sánchez-Barricarte, J. J. (2017). <a href="https://www.cambridge.org/core/services/aop-cambridge-core/content/view/51D48C611E5176A042FF28684041D997/S0021932016000547a.pdf/changes_in_sex_ratio_at_birth_in_china_a_decomposition_by_birth_order.pdf">Changes in sex ratio at birth in china: a decomposition by birth order</a>. <em>Journal of Biosocial Science</em>, 49(6), 826-841.{/ref} Here we see that since 1980 –a period in the middle of a rapid <a href="https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=CHN">reduction from 4 to 2 children per woman</a> – there has been some rise in the male bias for first-born children (rising from the expected 105 boys to 114 boys per 100 girls). But we see a much more significant skew in the ratio for second or third-born children. For third-born children, the ratio was 158 boys per 100 girls, suggesting a high prevalence of sex selection abortions.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>South Korea provides an important example where the male bias can be successfully addressed. But for several countries across Asia this looks like a major challenge: the data shows that many parents still strongly prefer a son.</p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe style="width: 100%; height: 600px; border: 0px none;" src="https://ourworldindata.org/grapher/sex-ratio-at-birth-by-birth-order"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":3} --> <h3>Sex ratio in childhood</h3> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Sex ratios – the ratio of males and females – at birth is male-biased across every country in the world; in <a href="https://ourworldindata.org/gender-ratio#sex-ratio-at-birth">our section on this</a>, we explain why biologically we'd expect this to be the case. The so-called <a href="https://ourworldindata.org/gender-ratio#definitions">'expected' sex ratio at birth</a> was around 105 males per 100 females. But how does this ratio look later in childhood? Does it change from newborns to five-years-olds?</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the two charts here we see two perspectives: firstly a global map of the sex ratio at five years old. Just as with the sex ratio at birth, we see the highest ratios in several Asian countries where the share of boys is higher than we would expect. In China, there is close to 115 boys per 100 girls at age five; in India, there are more than 109 boys per 100 girls.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Secondly we see a scatterplot comparison of the sex ratio at birth (on the y-axis) versus the ratio at five years old (on the x-axis). The grey line here represents parity: a country which lies along this line has the same ratio at five years old as it does for birth. As we see, most countries lie above this line: this means the sex ratio for newborns is higher than for 5-year-olds.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In other words, the male-bias tends to weaken through the first years of childhood. Why is this the case? As we explore in the next section of this entry: across most countries infant and child mortality rates are higher for boys than for girls. This means fewer boys survive the first few years of life. For most countries this results in a decline in the sex ratio.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Overall we see that despite higher child mortality in boys, the sex ratio at age five in the majority of countries is over 100: this means boys still outnumber girls in childhood.</p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe style="width: 100%; height: 600px; border: 0px none;" src="https://ourworldindata.org/grapher/sex-ratio-at-five-years-old"></iframe> <!-- /wp:html --> <!-- wp:html --> <iframe style="width: 100%; height: 600px; border: 0px none;" src="https://ourworldindata.org/grapher/sex-ratio-at-birth-vs-five-years-old"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":3} --> <h3>Why do boys die more often than girls?</h3> <!-- /wp:heading --> <!-- wp-block-tombstone 26840 --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">From</span> <a href="https://ourworldindata.org/life-expectancy"><span style="font-weight: 400;">life expectancy</span></a><span style="font-weight: 400;"> to</span><a href="https://ourworldindata.org/mental-health"> <span style="font-weight: 400;">mental health</span></a><span style="font-weight: 400;">;</span><a href="https://ourworldindata.org/substance-use"> <span style="font-weight: 400;">substance use</span></a><span style="font-weight: 400;"> to</span><a href="https://ourworldindata.org/cancer"> <span style="font-weight: 400;">cancer rates</span></a><span style="font-weight: 400;">; there are important differences in health outcomes between the sexes. In a related post, my colleague Esteban Ortiz-Ospina looks at the evidence to answer the question "</span><a href="https://ourworldindata.org/why-do-women-live-longer-than-men"><span style="font-weight: 400;">Why do women live longer than men?</span></a><span style="font-weight: 400;">"</span></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">Here we focus on the youngest, asking, why do young boys die more often than girls?</span></p> <!-- /wp:paragraph --> <!-- wp:heading {"level":4} --> <h4>Child and infant mortality is higher for boys in nearly all countries</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Child mortality measures the share of newborns who die before reaching their 5th birthday.&nbsp;In the chart below we see the comparison of child mortality by sex.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Here, the mortality rate for boys is shown on the y-axis, and the mortality rate for girls on the x-axis. The grey line running diagonally across the chart marks where the mortality rate for both sexes is equal. In countries which lie above the grey line, the rate for boys is higher than for girls.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>What's striking is that with exception of two countries – India and Tonga – child mortality is more common for boys in all countries of the world. This is also <a href="https://ourworldindata.org/grapher/infant-mortality-by-sex">true for infant mortality</a>, which is the share of newborns who die within their 1st year of life. We study why India and Tonga are outliers <a href="https://ourworldindata.org/gender-ratio#infanticide-and-excess-female-mortality"><strong>here</strong></a>.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Over the past half-century in particular, child mortality has been falling rapidly across the world. This has been <a href="https://ourworldindata.org/grapher/child-mortality-line-chart-by-sex">true for boys and girls</a> alike.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>It has been known for a long time that the mortality of boys is higher. As early as 1786 the physician, Dr Joseph Clarke, read a paper to the Royal Society of London on his observations that <em>"mortality of males exceeds that of females in almost all stages of life, and particularly the earliest stages"</em>.{ref}Clarke, J., &amp; Price, R. (1786). XVII. Observations on some causes of the excess of the mortality of males above that of females. By Joseph Clarke, MD Physician to the Lying-in Hospital at Dublin. Communicated by the Rev. Richard Price, DDFRS in a letter to Charles Blagden, MD Sec. R. S. Philosophical Transactions of the Royal Society of London, (76), 349-362.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe style="width: 100%; height: 600px; border: 0px none;" src="https://ourworldindata.org/grapher/child-mortality-by-sex"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":4} --> <h4>What do infants die from?</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Why is it the case that boys die more often than girls? First of all, it's important to understand what young children die from.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">In this chart we see global mortality rates in infants across different causes in 2017. This data comes from the IHME's </span><i><span style="font-weight: 400;">Global Burden of Disease</span></i><span style="font-weight: 400;"> study, which provides estimates by sex – on the y-axis we have plotted mortality rates in boys, and on the x-axis for girls. Just like the charts above, causes which lie above the grey line are more common in boys.</span></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">The chart shows that for all major causes of death, mortality is higher in boys. The sex differences in the causes of infant deaths were already documented almost a century ago: in an impressive paper published in 1929, Bawkin explores the mortality sex ratio of specific diseases from countries across the world.</span>{ref}Bakwin, H. (1929).<a href="https://search.proquest.com/docview/1301822705?pq-origsite=gscholar"> The sex factor in infant mortality</a>. <em>Human Biology</em>, 1(1), 90.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">There are some causes –</span><a href="https://owid.cloud/hiv-aids"> <span style="font-weight: 400;">HIV/AIDS</span></a><span style="font-weight: 400;">, nutritional deficiencies, whooping cough, among others – for which the mortality rates are higher in girls. But overall, infant boys are more likely to die in childhood than girls.</span>{ref}Sawyer, C. C. (2012).<a href="https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1001287"> Child mortality estimation: estimating sex differences in childhood mortality since the 1970s</a>. <em>PLoS Medicine</em>, 9(8), e1001287.{/ref}{ref}Naeye, R. L., Burt, L. S., Wright, D. L., Blanc, W. A., &amp; Tatter, D. (1971).<a href="https://pediatrics.aappublications.org/content/48/6/902.short"> Neonatal mortality, the male disadvantage</a>. <em>Pediatrics</em>, 48(6), 902-906.{/ref}{ref}This is also the explanation<a href="http://www.searo.who.int/entity/health_situation_trends/data/chi/sex-diff-imr/en/"> reported by</a> the World Health Organization: "<em>Newborn girls have a biological advantage in survival over newborn boys. They have lesser vulnerability to perinatal conditions (including birth trauma, intrauterine hypoxia and birth asphyxia, prematurity, respiratory distress syndrome and neonatal tetanus), congenital anomalies, and such infectious diseases as intestinal infections and lower respiratory infections.</em>"{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">Boys are more vulnerable in two key ways: they are at higher risk of birth complications, and infectious disease. We explore the possible reasons for this below.</span></p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe style="width: 100%; height: 600px; border: 0px none;" src="https://ourworldindata.org/grapher/infant-death-rates-by-cause-by-sex"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":4} --> <h4>Boys are at higher risk of birth complications</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">From comparison of mortality rates in infant boys and girls, it becomes clear that boys are at higher risk of complications in the first few days of life: preterm births, asphyxia, birth defects and heart anomalies. But why?<br> <br>First of all, </span><b>boys are more likely to be born prematurely</b><span style="font-weight: 400;">: the share of boys born before full-term pregnancy is higher than for girls.</span>{ref}Peelen, M. J., Kazemier, B. M., Ravelli, A. C., De Groot, C. J., Van Der Post, J. A., Mol, B. W., … &amp; Kok, M. (2016).<a href="https://obgyn.onlinelibrary.wiley.com/doi/pdf/10.1111/aogs.12929"> Impact of fetal gender on the risk of preterm birth, a national cohort study</a>. <em>Acta obstetricia et gynecologica Scandinavica</em>, 95(9), 1034-1041.{/ref}&nbsp;This occurs naturally, but is exacerbated by the rate of induced preterm births. Boys tend to have a higher birthweight than girls – which can increase the risk of waiting to term to deliver – meaning that more boys are induced before the end of the pregnancy term.{ref}Zeitlin, J., Saurel-Cubizolles, M. J., de Mouzon, J., Rivera, L., Ancel, P. Y., Blondel, B., &amp; Kaminski, M. (2002).<a href="https://academic.oup.com/humrep/article/17/10/2762/607779"> Fetal sex and preterm birth: are males at greater risk?</a>. <em>Human Reproduction</em>, 17(10), 2762-2768.{/ref}&nbsp;The chart above shows that more boys die from preterm births. The fact that preterm births are more common for boys contributes to this.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">Although boys are, on average, heavier than girls at birth, </span><b>they are less physiologically mature at birth</b><span style="font-weight: 400;">.</span> <span style="font-weight: 400;">This means they are at higher risk of having delayed physiological function (such as lung function) and adverse neurological outcomes.</span>{ref}Peacock, J. L., Marston, L., Marlow, N., Calvert, S. A., &amp; Greenough, A. (2012).<a href="https://www.nature.com/articles/pr201150"> Neonatal and infant outcome in boys and girls born very prematurely</a>. <em>Pediatric Research</em>, 71(3), 305.{/ref}{ref}Hintz, S. R., Kendrick, D. E., Vohr, B. R., Poole, W. K., Higgins, R. D., &amp; Nichd Neonatal Research Network. (2006).<a href="https://onlinelibrary.wiley.com/doi/abs/10.1080/08035250600599727"> Gender differences in neurodevelopmental outcomes among extremely preterm, extremely‐low‐birthweight infants</a>. <em>Acta Paediatrica</em>, 95(10), 1239-1248.{/ref}&nbsp;For example, poorer lung function in newborn boys has been shown for both term and preterm infants.{ref}Jones, M., Castile, R., Davis, S., Kisling, J., Filbrun, D., Flucke, R., … &amp; Tepper, R. S. (2000).<a href="https://www.atsjournals.org/doi/full/10.1164/ajrccm.161.2.9903026"> Forced expiratory flows and volumes in infants: normative data and lung growth</a>. <em>American Journal of Respiratory and Critical Care Medicine</em>, 161(2), 353-359.{/ref}{ref}Hoo, A. F., Henschen, M., Dezateux, C., Costeloe, K., &amp; Stocks, J. (1998).<a href="https://www.atsjournals.org/doi/full/10.1164/ajrccm.158.3.9711057"> Respiratory function among preterm infants whose mothers smoked during pregnancy</a>. <em>American Journal of Respiratory and Critical Care Medicine</em>, 158(3), 700-705.{/ref}&nbsp;Studies have suggested that even in the case of straightforward pregnancies, lung maturation in boys lags that of girls by approximately one week.{ref}Fleisher, B., Kulovich, M. V., Hallman, M. I. K. K. O., &amp; Gluck, L. O. U. I. S. (1985).<a href="https://europepmc.org/abstract/med/4022494"> Lung profile: sex differences in normal pregnancy</a>. <em>Obstetrics and Gynecology</em>, 66(3), 327-330.{/ref}&nbsp;These differences in maturity at birth are not restricted to lung function.{ref}Peacock, J. L., Marston, L., Marlow, N., Calvert, S. A., &amp; Greenough, A. (2012).<a href="https://www.nature.com/articles/pr201150"> Neonatal and infant outcome in boys and girls born very prematurely</a>. <em>Pediatric Research</em>, 71(3), 305.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">The reason for this difference has been an important question for decades – the answer is still not clear. But there are some leading hypotheses: surfactant production for lung function has been observed earlier in female fetuses, leading to improved airway flow in the lungs; estrogen has been shown to affect lung development positively in females; males, on average, have a higher birthweight meaning they may trade-off increased size for functional development; and the uterus may be less hospitable to male fetuses – the introduction of a Y chromosome in females can create an immunoreactive response to the central nervous system.</span>{ref}DiPietro, J. A., &amp; Voegtline, K. M. (2017).<a href="https://www.sciencedirect.com/science/article/pii/S0306452215006958"> The gestational foundation of sex differences in development and vulnerability</a>. <em>Neuroscience</em>, 342, 4-20.{/ref}{ref}Townsel, C. D., Emmer, S. F., Campbell, W. A., &amp; Hussain, N. (2017).<a href="https://www.frontiersin.org/articles/10.3389/fped.2017.00006/full"> Gender differences in respiratory morbidity and mortality of preterm neonates</a>. <em>Frontiers in Pediatrics</em>, 5, 6.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">This, combined with a higher risk of premature birth may explain why boys have higher rates of asphyxia, respiratory infections and birth defects.</span></p> <!-- /wp:paragraph --> <!-- wp:heading {"level":4} --> <h4>Boys are at higher risk of infectious diseases</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">Boys are also at higher risk of infectious diseases such as syphilis,</span> <a href="https://owid.cloud/malaria"><span style="font-weight: 400;">malaria</span></a><span style="font-weight: 400;">, respiratory infections, tetanus and diarrheal diseases. This is more generally true for a broad range of infections, spanning person-to-person, vector-borne, blood-borne, and food and water borne diseases.</span>{ref}Giefing‐Kröll, C., Berger, P., Lepperdinger, G., &amp; Grubeck‐Loebenstein, B. (2015).<a href="https://onlinelibrary.wiley.com/doi/full/10.1111/acel.12326"> How sex and age affect immune responses, susceptibility to infections, and response to vaccination</a>. <em>Aging Cell</em>, 14(3), 309-321.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">We see this clearly when we compare mortality rates for boys and girls in the earlier chart. But why are boys more susceptible to infection?</span></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">Overall, boys have weaker immune systems. There are two key hypotheses for why.</span></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;"><b>The Y-chromosome in boys increases their vulnerability.</b> Biologically, males and females are differentiated by chromosomes: females have two X chromosomes (XX) and males one X and one Y chromosome (XY). Having two X chromosomes means that the newborn has a stronger immune system because X chromosomes contain a larger number of immune-related genes.</span>{ref}Markle, J. G., &amp; Fish, E. N. (2014).<a href="https://www.sciencedirect.com/science/article/pii/S1471490613001592"> SeXX matters in immunity</a>. <em>Trends in Immunology</em>, 35(3), 97-104.{/ref}{ref}Libert, C., Dejager, L., &amp; Pinheiro, I. (2010).<a href="https://www.nature.com/articles/nri2815"> The X chromosome in immune functions: when a chromosome makes the difference</a>. <em>Nature Reviews Immunology</em>, 10(8), 594.{/ref}&nbsp;This means that, since females have two X chromosomes, they have a stronger immune response; boys on the other hand, are more vulnerable to X-linked infections.{ref}Waldron, I. (1983). Sex differences in human mortality: the role of genetic factors.<a href="https://www.sciencedirect.com/science/article/pii/0277953683902344"> <em>Social Science &amp; Medicine</em></a>, 17(6), 321-333.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">This makes males more vulnerable to many infectious diseases. They are also more susceptible to specific genetic diseases where the defective genes are carried on either the X or Y chromosomes; this is because boys have only one X chromosome so a single recessive gene on that X chromosome results in the disease.</span></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">But the stronger immune response of females comes with a cost. It’s the reason why women are more susceptible to autoimmune disorders such as HIV/AIDS.</span>{ref}Libert, C., Dejager, L., &amp; Pinheiro, I. (2010).<a href="https://www.nature.com/articles/nri2815"> The X chromosome in immune functions: when a chromosome makes the difference</a>. <em>Nature Reviews Immunology</em>, 10(8), 594.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><b>Sex hormones may be another key reason for weaker immune systems in males. </b><span style="font-weight: 400;">Males have much higher amounts of testosterone which seem to inhibit two major parts of the immune system – B and T-lymphocytes.</span>{ref}Fischer, J., Jung, N., Robinson, N., &amp; Lehmann, C. (2015).<a href="https://link.springer.com/article/10.1007/s15010-015-0791-9"> Sex differences in immune responses to infectious diseases</a>. <em>Infection</em>, 43(4), 399-403.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">Estrogen, on the other hand, acts as an effective regulator of this. Overall, male hormones weaken the immune system relative to females.</span></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><strong>The male disadvantage</strong></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">The fact that boys are more susceptible than girls to a range of health conditions is often summarized as the “male disadvantage”. This is not restricted to childhood: the female advantage carries into adulthood. It’s part of the reason </span><a href="https://ourworldindata.org/why-do-women-live-longer-than-men"><span style="font-weight: 400;">why women tend to live longer than men</span></a><span style="font-weight: 400;">. </span></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">The leading explanations for the "male disadvantage" lie in the biological differences between the sexes. More specifically, differences in maturity, sex chromosomes, and hormones.</span></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">In circumstances where both sexes are treated equally, we would therefore expect infant and child mortality rates to be slightly higher for boys.</span></p> <!-- /wp:paragraph --> <!-- wp:heading {"level":3} --> <h3>Sex ratio through adulthood</h3> <!-- /wp:heading --> <!-- wp:paragraph --> <p>The sex ratio – the number of males relative to females – at birth and in childhood are male-biased in almost every country.<br> In previous discussion we covered why we'd expected this to be the case biologically.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>How does the sex ratio change throughout adulthood?</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In this chart we see the sex ratio – measured as the number of males per 100 females – at different ages through adolescence and adulthood.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the global average for adolescents and young adults we see the result of both the male-bias in birth ratios and the large impact of populous countries such as China and India with very skewed sex ratios: At age 15 and 20, males outnumber females by 106 to 100.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>But as we move through adulthood we see that this ratio is lower and lower. For 50-year-olds the ratio is close to 1-to-1; for 70-year-olds there are only 86 males per 100 females; and in the very oldest age bracket (people aged 100 and older) there are only 24 men per 100 women.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>You can explore this data for any country of region of the world using the "change country" button in the top-left of the chart. You will see that for some countries this decline in the sex ratio with age is even more extreme: in Russia, for example, by age 50 there are only 91 males per 100 females; by 70 years old there are almost twice as many women as men.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In every country in the world <a rel="noopener noreferrer nofollow" data-token-index="1" data-reactroot="" href="https://ourworldindata.org/grapher/life-expectancy-of-women-vs-life-expectancy-of-women" target="_blank">women tend to live longer than men</a>. Whilst this is true today, it hasn't always been the case. In his text '<a rel="noopener noreferrer nofollow" data-token-index="3" data-reactroot="" href="https://ourworldindata.org/why-do-women-live-longer-than-men" target="_blank">Why do women live longer than men?</a>' my colleague Esteban takes a look at the evidence and explanations for why this is the case.</p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe style="width: 100%; height: 600px; border: 0px none;" src="https://ourworldindata.org/grapher/sex-ratio-by-age"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":3} --> <h3>Why do women live longer than men?</h3> <!-- /wp:heading --> <!-- wp:paragraph --> <p>On average, women live longer than men – this is true for every country in the world. This fact plays an important role in how the sex ratio changes with age through adulthood.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>A detailed discussion of why this is the case is available in our explainer on '<a href="https://ourworldindata.org/why-do-women-live-longer-than-men">Why do women live longer than men?</a>'.</p> <!-- /wp:paragraph --> <!-- wp:heading --> <h2>Missing girls and women</h2> <!-- /wp:heading --> <!-- wp:heading {"level":3} --> <h3>Biology or discrimination: which countries have skewed sex ratios at birth?</h3> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Today, and at several points historically, the sex ratio at birth in some countries is too skewed to be explained by biological differences alone. The <a href="https://ourworldindata.org/gender-ratio#definitions">'expected' sex ratio at birth</a> is around 105 males per 100 females.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In a recent study Chao et. al (2019) re-modelled sex ratios at birth (SRB) across the world based on a range of population sources, including census and household survey data.{ref}Chao, F., Gerland, P., Cook, A.R., Alkema, L. (2019). <a href="https://www.pnas.org/content/early/2019/04/09/1812593116">Systematic assessment of the sex ratio at birth for all countries and estimation of national imbalances and regional reference levels</a>. <em>PNAS</em>.{/ref} The results are shown in the chart below since 1950. The authors identified 12 countries with strong statistical evidence of a skewed sex ratio: Albania, Armenia, Azerbaijan, China, Georgia, Hong Kong, India, Montenegro, South Korea, Taiwan, Tunisia, and Vietnam.{ref}Note that this does not imply that other countries do not have male preference or some evidence of a skewed sex ratio. Results of the Chao et al. (2019) study highlight those with the strongest statistical evidence of this imbalance.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe style="width: 100%; height: 600px; border: 0px none;" src="https://ourworldindata.org/grapher/sex-ratio-at-birth-males-chao-et-al"></iframe> <!-- /wp:html --> <!-- wp:paragraph --> <p>Most of these countries are in Asia. Why is this the case? Is there a biological or environmental difference, or is it the result of discrimination?</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><b>Hepatitis B was proposed then later debunked</b><br>Amartya Sen was the first scholars to publicly bring attention to the concept of "missing women" as a result of sex selective abortion, unequal treatment and infanticide of girls.{ref}Sen, Amartya (20 December 1990). <a href="https://web.archive.org/web/20130504072819/http://ucatlas.ucsc.edu/gender/Sen100M.html">More Than 100 Million Women Are Missing</a>. <em>New York Review of Books</em>. 37 (20).{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The reason for this skew in sex ratio has been previously challenged. One of the leading hypotheses was put forward by economist Emily Oster. In a 2005 paper she argued that a large proportion – approximately 45%, around 75% in China, 20-50% in Egypt and western Asia, and under 20% in India, Bangladesh, Pakistan, and Nepal – of the overrepresentation of men could be explained by the high rates of hepatitis B carriers in Asia.{ref}Oster, E. (2005). <a href="https://www.journals.uchicago.edu/doi/abs/10.1086/498588">Hepatitis B and the Case of the Missing Women</a>. <em>Journal of Political Economy</em>, 113(6), 1163-1216.{/ref} The rationale was that (1) hepatitis B carriers have an offspring sex ratio much more in favour of boys (1.5 boys per girl), and (2) that hepatitis B carrier rates were notably higher in Asian cultures than in the West. The combination of these two observations Oster calculated could account for a large proportion of the "missing women".</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>A few years later, Oster debunked her own hypothesis on the role of hepatitis B in a paper titled "Hepatitis B does not explain male-biased sex ratios in China". In a study of 67,000 people in China – 15% of which were hepatitis B carriers – Oster and colleagues found no link between hepatitis B status and offspring sex ratio.{ref}Oster, E., Chen, G., Yu, X., &amp; Lin, W. (2010). <a href="https://www.nber.org/papers/w13971">Hepatitis B does not explain male-biased sex ratios in China</a>. <em>Economics Letters</em>, 107(2), 142-144.{/ref} The hepatitis carrier status of neither the mother or the father had an effect on the offspring sex: carriers were not more likely to have a boy than non-carriers. The authors concluded that hepatitis B rates could not explain the skewed sex ratio in China.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Other studies – such as that by Lin and Luoh (2008) in Taiwan – have also found minimal to no effect of hepatitis B on the sex ratio.{ref}Lin, M. J., &amp; Luoh, M. C. (2008). <a href="https://www.jstor.org/stable/29730171">Can hepatitis B mothers account for the number of missing women? Evidence from three million newborns in Taiwan</a>. <em>American Economic Review</em>, 98(5), 2259-73.{/ref}{ref}Monica Das Gupta, <a href="https://academic.oup.com/wbro/article-abstract/23/2/201/1662748">Can Biological Factors Like Hepatitis B Explain the Bulk of Gender Imbalance in China? A Review of the Evidence</a>, <em>The World Bank Research Observer</em>, Volume 23, Issue 2, Fall 2008, Pages 201–217.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><b>Sex-selective abortions and discrimination against girls</b><br>After the hepatitis B hypothesis was debunked, no clear evidence of a biological factor in such skewed sex ratios has emerged. There is some variability in the <a href="https://ourworldindata.org/gender-ratio#definitions">"expected" sex ratio</a> which may result from biological or environmental factors – a figure of 105 boys per 100 girls is usually adopted, but often this can vary from 103 to 107 boys per 100 girls. But the natural variability of the sex ratio is too small to explain the high ratios in some countries.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The evidence for sex-selective abortion and discrimination against girls is now strong across several countries. Not only does the increase in sex ratios coincide with the availability of prenatal sex determination technologies, there is also clear evidence from studies investigating the use and promotion of such methods.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In India, for example, prenatal diagnosis (PD) became available in the 1970s, shortly after legalization of medical abortion in 1971.{ref}Madan, K., &amp; Breuning, M. H. (2014). <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4052431/">Impact of prenatal technologies on the sex ratio in India: an overview</a>. <em>Genetics in Medicine</em>, 16(6), 425.{/ref} Whilst its use was intended for detection of abnormalities, it was soon used and promoted by the Indian medical profession for sex determination.{ref}Sharma, B. R., Gupta, N., &amp; Relhan, N. (2007). <a href="https://www.sciencedirect.com/science/article/pii/S0033350607000960">Misuse of prenatal diagnostic technology for sex-selected abortions and its consequences in India</a>. <em>Public Health</em>, 121(11), 854-860.{/ref} Even after its use for sex determination was prohibited, studies suggest many gynecologists did not consider sex-selection abortion to be unethical and argued that it was an important intervention to balance population control with the desire for sons.{ref}Correspondent, L. I. (1983). <a href="https://www.ncbi.nlm.nih.gov/pubmed/11644254">Misuse of amniocentesis</a>. <em>Lancet</em>, 321, 812-813.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Results from some of the earliest studies on abortions following the availability of prenatal sex determination are striking. Over the year from 1976 to 1977, at an urban hospital in India, 96% of the girls who were tested were aborted; in contrast, all of the 250 boys tested – including those with an identified risk of genetic defect – were born.{ref}Ramanamma, A., &amp; Bambawale, U. (1980). <a href="https://www.sciencedirect.com/science/article/pii/0160798780900599">The mania for sons: an analysis of social values in South Asia</a>. <em>Social Science &amp; Medicine. Part B: Medical Anthropology</em>, 14(2), 107-110.{/ref} At a clinic in Mumbai, all of the 15,914 abortions after sex determination in 1984/85 were girls. Results from another six hospitals in the city found 7,999 of the 8,000 aborted fetuses in 1988 were girls.{ref}Tandon SL, Sharma R. (2006). <a href="http://www.sascv.org/ijcjs/previousissues.html">Female foeticide and infanticide in India: an analysis of crimes against girl children</a>. <em>International Journal of Criminal Justice Science</em>.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The evidence that highly skewed sex ratios at birth have been largely the result of gender discrimination and selective abortions has been well-established across several countries. We discuss the reasons for this discrimination <a href="https://ourworldindata.org/gender-ratio#why-is-there-preference-for-a-son"><strong>here</strong></a>.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>There are some additional hypotheses as to why the sex ratio at birth is skewed in some countries. Based on Chinese census data, Shi and Kennedy (2016) argue that the skew in China's sex ratio is not the result of selective abortion practices, but much more the result of administrative anomalies.{ref}Shi, Y., &amp; Kennedy, J. J. (2016). <a href="https://www.cambridge.org/core/journals/china-quarterly/article/delayed-registration-and-identifying-the-missing-girls-in-china/0759987A48A37E3D2CFE157778747E33">Delayed registration and identifying the “missing girls” in China</a>.&nbsp;<em>The China Quarterly</em>,&nbsp;<em>228</em>, 1018-1038.{/ref} The authors argue that the one-child policy led some parents to postpone the registration of daughters (making them appear "missing"), but that they appear later in Chinese census data. A year later, Cai (2017) challenged the authors' conclusions in support of the conventional hypothesis that this is not a statistical artefact, but a real demographic&nbsp; and social challenge.{ref}Cai, Y. (2017). <a href="https://www.cambridge.org/core/journals/china-quarterly/article/missing-girls-or-hidden-girls-a-comment-on-shi-and-kennedys-delayed-registration-and-identifying-the-missing-girls-in-china/61E21855F8A1D958660973841BBC46FD">Missing Girls or Hidden Girls? A Comment on Shi and Kennedy's “Delayed Registration and Identifying the ‘Missing Girls’ in China”</a>.&nbsp;<em>The China Quarterly</em>,&nbsp;<em>231</em>, 797-803.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:heading {"level":3} --> <h3>Infanticide</h3> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Sex discrimination can occur prenatally (in the form of sex-selective abortions, as we discuss <a href="https://ourworldindata.org/gender-ratio#biology-or-discrimination-which-countries-have-skewed-sex-ratios-at-birth"><strong>here</strong></a>) or postnatally when it can lead to the death of a child in the very worst cases. The death of a child due to sex discrimination can be brought about in a deliberate killing of an infant (infanticide) or can be caused by neglect or poor and unequal treatment.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Over time, prenatal discrimination has increased as both abortions and sex determination technologies have become more readily available. Nonetheless, postnatal discrimination still occurs and has a long history.</p> <!-- /wp:paragraph --> <!-- wp:heading {"level":4} --> <h4><b>Infanticide has a long history</b></h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Infanticide (or infant homicide) – the deliberate killing of newborns and infants – has a long history.{ref}Moseley, K. L. (1985).<a href="https://heinonline.org/HOL/LandingPage?handle=hein.journals/ilmed1&amp;div=42&amp;id=&amp;page="> The history of infanticide in Western society</a>. <em>Issues in Law &amp; Medicine</em>, 1, 345.{/ref}{ref}Levittan, M. (2012). The history of infanticide: exposure, sacrifice, and femicide. <em>Violence and Abuse in Society. Understanding a Global Crisis</em>. Santa Barbara, ABC-CLIO, 83-130.{/ref}&nbsp;From hunter-gatherers to ancient civilizations to the present day: infanticide has spanned all periods of history. In fact, anthropologist Laila Williamson goes as far to say: “Infanticide has been practiced on every continent and by people on every level of cultural complexity, from hunter gatherers to high civilizations, including our own ancestors. Rather than being an exception, then, it has been the rule."{ref}Williamson, Laila (1978). "Infanticide: an anthropological analysis". In Kohl, Marvin (ed.). <em>Infanticide and the Value of Life</em>. NY: <a href="https://en.wikipedia.org/wiki/Prometheus_Books">Prometheus Books</a>. pp. 61–75.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">And humans are not alone. From birds to rodents; fish to mammals; we find evidence of infanticide across the animal kingdom.</span>{ref}Hausfater, G., &amp; Hrdy, S. B. (2017). <em>Infanticide: comparative and evolutionary perspectives</em>. Routledge.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">There are some common misconceptions today surrounding the practice of infanticide. Although the term is now often adopted as a synonym for ‘female infanticide’ – the killing of unwanted girls – the gender specifics and drivers of infanticide depend on context and time in history.</span>{ref}Scott, E. (2017, June). <a href="https://books.google.co.uk/books?hl=en&amp;lr=&amp;id=n98jDwAAQBAJ&amp;oi=fnd&amp;pg=PA143&amp;dq=unpicking+a+myth:+the+infanticide&amp;ots=2XS6lFMoJO&amp;sig=AdzrpXxZR3RWGNd-qf0FducA81I#v=onepage&amp;q=unpicking%20a%20myth%3A%20the%20infanticide&amp;f=false">Unpicking a myth: the infanticide of female and disabled infants in antiquity</a>. In <em>TRAC 2000: Proceedings of the Tenth Annual Theoretical Archaeology Conference. London 2000</em> (p. 143). Oxbow Books.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:heading {"level":4} --> <h4><b>Historical evidence and estimates of infanticide</b></h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p><b><span style="font-weight: 400;">A number of researchers have studied the demographic, health and cultural profiles of prehistoric societies. In rare cases they can use indirect evidence of the fossil record; but many rely on modern hunter-gatherer societies today.{ref}This of course introduces uncertainty as to how good an analogue modern hunter-gatherers are to prehistoric societies. Modern hunter-gatherer societies may have some contact and transfer with external influence. As a result, researchers often focus on societies with as little external influence as possible, for example having no nutritional, health, sanitation or technology transfer.{/ref}</span></b></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">Estimates for infanticide in prehistoric societies are very high. Using recent hunter-gatherer societies as a proxy, some studies suggest anywhere from 15% to 50% of newborns were killed in the first year of life.</span>{ref}Birdsell, Joseph, B. (1986). "Some predictions for the Pleistocene based on equilibrium systems among recent hunter gatherers". In Lee, Richard &amp; Irven DeVore (ed.). <em>Man the Hunter</em>. Aldine Publishing Co. p. 239.{/ref}&nbsp;Other estimates are lower, but still very high: in the range of 15-20%.{ref}Williamson, Laila (1978). "Infanticide: an anthropological analysis". In Kohl, Marvin (ed.). <em>Infanticide and the Value of Life</em>. NY: <a href="https://en.wikipedia.org/wiki/Prometheus_Books">Prometheus Books</a>. pp. 61–75.{/ref}<span style="font-weight: 400;"> </span></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">Hill &amp; Walker (2007) looked at the demographic profiles, death rates and causes of death of recent hunter-gatherers: the Hiwi group of Venezuela. They did this using census and interviews gathered over a seven year period.</span>{ref}Hill, K., Hurtado, A. M., &amp; Walker, R. S. (2007). <a href="https://www.sciencedirect.com/science/article/pii/S0047248406002193">High adult mortality among Hiwi hunter-gatherers: Implications for human evolution</a>. <em>Journal of Human Evolution</em>, <em>52</em>(4), 443-454.{/ref}&nbsp;They found very high rates of infant death from violence. Infant mortality rates in the past were very high – most studies suggest around a quarter of newborns did not survive the first year of life.&nbsp;<span style="font-weight: 400;">In the Hiwi hunter-gatherers, researchers found homicide to be the second largest cause of death, accounting for 30%. They also found large sex differences: infanticide rates were four times higher for girls than boys.</span></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">Other studies of modern hunter-gatherer societies analysed the sex ratio of infants to estimate the prevalence of infanticide. Very skewed sex ratio of infants is suggestive of select infanticide. In studying 86 hunter-gatherer bands across North America, South America, Africa, Asia and Australia, researchers found high levels of female infanticide across 77 of them.</span>{ref}Divale, W. T. (1972). <a href="https://www.tandfonline.com/doi/abs/10.1080/00438243.1972.9979534">Systemic population control in the middle and upper palaeolithic: Inferences based on contemporary hunter‐gatherers</a>. <em>World Archaeology</em>, <em>4</em>(2), 222-243.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">This is shown in the table, where there were many more young males than females in bands where infanticide was reported as ‘common’ or ‘occasional’.</span></p> <!-- /wp:paragraph --> <!-- wp:shortcode --> <table><thead><tr><th scope="col" colSpan="1">Infanticide reported as:</th><th scope="col" colSpan="1">Youth sex ratio <br>(males per 100 females)</th><th scope="col" colSpan="1">Adult sex ratio <br>(males per 100 females)</th><th scope="col" colSpan="1">Number of hunter-gathering bands</th></tr></thead><tbody><tr><td colSpan="1" rowspan="1">Common</td><td colSpan="1" rowspan="1">138</td><td colSpan="1" rowspan="1">105</td><td colSpan="1" rowspan="1">71</td></tr><tr><td colSpan="1" rowspan="1">Occasional</td><td colSpan="1" rowspan="1">138</td><td colSpan="1" rowspan="1">80</td><td colSpan="1" rowspan="1">6</td></tr><tr><td colSpan="1" rowspan="1">Not common</td><td colSpan="1" rowspan="1">100</td><td colSpan="1" rowspan="1">85</td><td colSpan="1" rowspan="1">3</td></tr><tr><td colSpan="1" rowspan="1">Not practised</td><td colSpan="1" rowspan="1">94</td><td colSpan="1" rowspan="1">83</td><td colSpan="1" rowspan="1">6</td></tr></tbody></table> <!-- /wp:shortcode --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">The practice of infanticide was not just common in prehistoric societies, but was also very common in many – but not all – ancient cultures.</span>{ref}Langer, W. L. (1974). <a href="https://search.proquest.com/docview/1305583868">Infanticide: A historical survey</a>. <em>The Journal of Psychohistory</em>, <em>1</em>(3), 353.{/ref}&nbsp;Evidence for this exists either in the form of preserved burial remains, documented records or writings suggestive of the practice.{ref}Milner, Larry S. (2000). <em>Hardness of Heart / Hardness of Life: The Stain of Human Infanticide</em>. Lanham/New York/Oxford: University Press of America.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:heading {"level":4} --> <h4><b>Both sexes</b> are victims of infanticide</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">It’s a common assumption that infanticide relates only to female infanticide: the killing of unwanted girls.</span>{ref}Scott, E. (2017, June). <a href="https://books.google.co.uk/books?hl=en&amp;lr=&amp;id=n98jDwAAQBAJ&amp;oi=fnd&amp;pg=PA143&amp;dq=unpicking+a+myth:+the+infanticide&amp;ots=2XS6lFMoJO&amp;sig=AdzrpXxZR3RWGNd-qf0FducA81I#v=onepage&amp;q=unpicking%20a%20myth%3A%20the%20infanticide&amp;f=false">Unpicking a myth: the infanticide of female and disabled infants in antiquity</a>. In <em>TRAC 2000: Proceedings of the Tenth Annual Theoretical Archaeology Conference. London 2000</em> (p. 143). Oxbow Books.{/ref}&nbsp;But the role or direction of gender discrimination – either towards boys or girls – is context-dependent.{ref}Hughes, A. L. (1981). <a href="https://www.sciencedirect.com/science/article/pii/0162309581900236">Female infanticide: Sex ratio manipulation in humans</a>. <em>Ethology and Sociobiology</em>, 2(3), 109-111.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">Sometimes here is no clear gender discrimination, and it occurs for both sexes.</span></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">There is of course significant evidence of female-selective infanticide throughout history: we see that in the sex ratio of many hunter-gatherer societies above through to skewed ratios in Medieval England.</span>{ref}Kellum, B. A. (1974). <a href="https://search.proquest.com/openview/c1ae81634e9d46b2e7402da67bc5eeef/1?pq-origsite=gscholar&amp;cbl=1816657">Infanticide in England in the later Middle Ages</a>. <em>The Journal of Psychohistory</em>, <em>1</em>(3), 367.{/ref}&nbsp;Evidence of male-selective infanticide is rarer, but does exist: in a sample of 93 preindustrial culture, 9 showed evidence of female-selective, while 1 showed male-selective infanticide.{ref}Hughes, A. L. (1981). <a href="https://www.sciencedirect.com/science/article/pii/0162309581900236">Female infanticide: Sex ratio manipulation in humans</a>. <em>Ethology and Sociobiology</em>, 2(3), 109-111.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">Even today, cases on infanticide still exist, despite being outlawed in most countries.</span>{ref}Cecilia Lai‐wan, C., Eric, B., &amp; Celia Hoi‐yan, C. (2006).<a href="https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=Cecilia+Lai%E2%80%90wan%2C+C.%2C+Eric%2C+B.%2C+%26+Celia+Hoi%E2%80%90yan%2C+C.+%282006%29.+Attitudes+to+and+practices+regarding+sex+selection+in+China.+Prenatal+Diagnosis%3A+Published+in+Affiliation+With+the+International+Society+for+Prenatal+Diagnosis%2C+26%287%29%2C+610-613.&amp;btnG="> Attitudes to and practices regarding sex selection in China</a>. <em>Prenatal Diagnosis: Published in Affiliation With the International Society for Prenatal Diagnosis</em>, 26(7), 610-613.{/ref} Infanticide occurs in Western countries: in some (such as the United States) boys make up a higher share of infant homicides.{ref}Porter, T., &amp; Gavin, H. (2010). <a href="https://journals.sagepub.com/doi/abs/10.1177/1524838010371950">Infanticide and neonaticide: a review of 40 years of research literature on incidence and causes</a>. <em>Trauma, Violence, &amp; Abuse</em>, <em>11</em>(3), 99-112.{/ref}&nbsp;But the most widely prevalent – and selection that has a significant impact on gender ratio – is female infanticide. This remains reported across countries with a strong son preference: India and China are the most documented examples.{ref}Chunkath, S. R., &amp; Athreya, V. B. (1997). <a href="https://www.jstor.org/stable/4405340">Female infanticide in Tamil Nadu: some evidence</a>. <em>Economic and political weekly</em>, WS21-WS28.{/ref}{ref}Lee, B. J. (1981). <a href="https://www.jstor.org/stable/41298766">Female infanticide in China</a>. <em>Historical Reflections/Réflexions Historiques</em>, 163-177.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span style="font-weight: 400;">Infanticide is the most direct case of postnatal sex selection. More often overlooked is the excess mortality which results from neglect and unequal treatment of girls. This is ‘excess female mortality’ is sometimes often referred to as ‘delayed infanticide’.</span></p> <!-- /wp:paragraph --> <!-- wp:heading {"level":3} --> <h3>Excess female mortality</h3> <!-- /wp:heading --> <!-- wp:paragraph --> <p><b>Poor treatment of girls results in increased mortality in childhood</b><br>In almost every country young boys are more likely to die in childhood than girls – as we explore <a href="https://ourworldindata.org/gender-ratio#why-do-boys-die-more-often-than-girls"><strong>here</strong></a>, there are several biological reasons for is. But this is not true in a few counties – India is one notable example today. There, girls die more often than boys.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>When we compare infant (under one year old) and child (under-5s) mortality rates between boys and girls in India we see that the difference is bigger for the older age group. While infant mortality rates are approximately the same, the child mortality rate for girls is higher.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Let's then focus on children rather than infants. In the chart here we see mortality rates for boys (on the y-axis) and girls (on the x-axis) for various causes in India. This data is shown for children aged 1-4 years old in 2017. Here we see that for many, death rates are significantly higher for girls. Some of these – hepatitis, measles or tuberculosis, for example – we expect to be higher for girls. But not for infections, respiratory and diarrheal diseases. Note also the much higher mortality rates for nutritional deficiencies and protein-energy malnutrition for girls.</p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe style="width: 100%; height: 600px; border: 0px none;" src="https://ourworldindata.org/grapher/child-deaths-by-cause-by-sex-india"></iframe> <!-- /wp:html --> <!-- wp:paragraph --> <p>Poorer health outcomes for girls across some countries – often in Asia and not restricted to India – has been well-documented.{ref}Million Death Study Collaborators. (2010). <a href="https://www.sciencedirect.com/science/article/pii/S0140673610614614">Causes of neonatal and child mortality in India: a nationally representative mortality survey</a>. <em>The Lancet</em>, 376(9755), 1853-1860.{/ref}{ref}Raj, A., McDougal, L. P., &amp; Silverman, J. G. (2015). <a href="https://link.springer.com/article/10.1007/s10995-014-1513-0">Gendered effects of siblings on child malnutrition in South Asia: cross-sectional analysis of demographic and health surveys from Bangladesh, India, and Nepal</a>. <em>Maternal and Child Health Journal</em>, 19(1), 217-226.{/ref} Even for some countries where the child mortality rate remains higher in boys than for the girls, death rates for girls are still higher than would be expected.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Social preference for a boy has resulted in unequal treatment of young girls in a number of ways. Studies have shown in some countries:</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li>poorer nutrition for girls and unequal food distribution;{ref}Aurino, E. (2017). <a href="https://www.sciencedirect.com/science/article/pii/S1570677X16301666">Do boys eat better than girls in India? Longitudinal evidence on dietary diversity and food consumption disparities among children and adolescents</a>. <em>Economics &amp; Human Biology</em>, 25, 99-111.{/ref}</li><li>less breastfeeding from mothers for daughters than for sons;{ref}Jayachandran, S., &amp; Kuziemko, I. (2011). <a href="https://academic.oup.com/qje/article-abstract/126/3/1485/1854553">Why do mothers breastfeed girls less than boys? Evidence and implications for child health in India</a>. <em>The Quarterly Journal of Economics</em>, 126(3), 1485-1538.{/ref}</li><li>lower healthcare utilization for girls;{ref}Ghosh, N., Chakrabarti, I., Chakraborty, M., &amp; Biswas, R. (2013). <a href="https://www.ijmedph.org/article/60?qt-sidebar_tabs=2">Factors affecting the healthcare-seeking behavior of mothers regarding their children in a rural community of Darjeeling district, West Bengal</a>. <em>International Journal of Medicine and Public Health</em>, 3(1).{/ref}{ref}Barcellos, S. H., Carvalho, L. S., &amp; Lleras-Muney, A. (2014). <a href="https://www.aeaweb.org/articles?id=10.1257/app.6.1.157">Child gender and parental investments in India: Are boys and girls treated differently?</a>. <em>American Economic Journal: Applied Economics</em>, 6(1), 157-89.{/ref}</li><li>during pregnancy there is evidence of preferential treatment for boys with more antenatal visits and increased tetanus vaccinations.{ref}Bharadwaj, P., &amp; Lakdawala, L. K. (2013). <a href="https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=Bharadwaj%2C+P.%2C+%26+Lakdawala%2C+L.+K.+%282013%29.+Discrimination+begins+in+the+womb%3A+Evidence+of+sex-selective+prenatal+investments.+Journal+of+Human+Resources%2C+48%281%29%2C+71-113.&amp;btnG=">Discrimination begins in the womb: Evidence of sex-selective prenatal investments</a>. <em>Journal of Human Resources</em>, 48(1), 71-113.{/ref}</li></ul> <!-- /wp:list --> <!-- wp:paragraph --> <p>This combination of poorer nutrition and healthcare investment can result in higher mortality rates for girls, but also to excess mortality for women in later stages of life.</p> <!-- /wp:paragraph --> <!-- wp:heading {"level":3} --> <h3>How many women are missing?</h3> <!-- /wp:heading --> <!-- wp:paragraph --> <p>The term 'missing women' was first coined by Indian economist Amartya Sen in a 1990 article; he estimated "more than 100 million women are missing".{ref}Sen, A. (1990). <a href="http://www.ouazad.com/nyustats/resources/reading-week1.pdf">More than 100 million women are missing</a>. <em>The New York Review of Books</em>, 37(20), 61-66.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>'Missing women' refers to the shortfall of women from the number we would expect in the absence of sex discrimination. It is the sum of women who are missing at birth (as a result of sex-selective prenatal practices such as abortion) and excess female mortality later in life (either through infanticide, child neglect or maltreatment).</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Many researchers have tried to calculate the number of missing women. Using sex ratios at birth, and at different ages we can compare the observed and expected values: the difference is then defined as girls and women who are missing.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>There are very obvious challenges in calculating this figure. For the observed sex ratio, there is the concern of how accurate the reported number of births, males and females are. The other major issue is knowing exactly what the baseline/expected ratio of males to females would be at each stage in life. For example, the <a href="https://ourworldindata.org/gender-ratio#definitions">'expected' sex ratio at birth</a> is quoted as 105 male births per 100 female births. But through time and across the world, this can often vary between 103 to 107 male births per 100 female births. The combination of these measurement issues means any estimate of the number of missing women will come with fairly high uncertainty.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the table here we provide a summary of a range of estimates – note here that the year of the estimate is different for each.<b> </b>Here we see that although there is significant uncertainty in these estimates, all are within the range of over 50 million by 1990, and likely upwards of 100 million today.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the chart we see some of the most recent estimates of missing women from 1970 through to 2015 from Bongaarts &amp; Guilmoto (2015).{ref}Bongaarts, J., &amp; Guilmoto, C. Z. (2015). <a href="https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=doi.org%2F10.1111%2Fj.1728-4457.2015.00046.x&amp;btnG=">How many more missing women? Excess female mortality and prenatal sex selection, 1970–2050</a>. <em>Population and Development Review</em>, 41(2), 241-269.{/ref} In 1970 the researchers estimated there were 61 million missing women; by 2015, 136 million. This is more than the <a rel="noopener noreferrer nofollow" data-token-index="1" data-reactroot="" href="https://ourworldindata.org/grapher/population-by-country-gapminder+un?tab=chart&amp;time=1800..2019&amp;country=MEX" target="_blank">population of Mexico</a>. We see that more than 80% are missing from China and India – 68 and 45 million, respectively.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The authors also provided projections of the number of missing women through demographic changes to 2050 which you <a href="https://ourworldindata.org/grapher/global-number-of-missing-women"><strong>find here</strong></a>.</p> <!-- /wp:paragraph --> <!-- wp:shortcode --> <table><thead><tr><th scope="col" colSpan="1">Source</th><th scope="col" colSpan="1">Year estimate is for</th><th scope="col" colSpan="1">Number of missing women</th></tr></thead><tbody><tr><td colSpan="1" rowspan="1">Sen (1990, 1992)</td><td colSpan="1" rowspan="1">1990</td><td colSpan="1" rowspan="1">More than 100 million</td></tr><tr><td colSpan="1" rowspan="1">Coale (1991)</td><td colSpan="1" rowspan="1">1990</td><td colSpan="1" rowspan="1">60 million</td></tr><tr><td colSpan="1" rowspan="1">Klasen (1994)</td><td colSpan="1" rowspan="1">1990</td><td colSpan="1" rowspan="1">92 million</td></tr><tr><td colSpan="1" rowspan="1">Klasen and Wink (2002)</td><td colSpan="1" rowspan="1">1990s</td><td colSpan="1" rowspan="1">102 million</td></tr><tr><td colSpan="1" rowspan="1">Hudson & Den Boer (2004)</td><td colSpan="1" rowspan="1">2000s</td><td colSpan="1" rowspan="1">90 million</td></tr><tr><td colSpan="1" rowspan="1">Guilmoto (2012)</td><td colSpan="1" rowspan="1">2010</td><td colSpan="1" rowspan="1">117 million</td></tr><tr><td colSpan="1" rowspan="1">Bongaarts & Guilmoto (2015)</td><td colSpan="1" rowspan="1">2015</td><td colSpan="1" rowspan="1">136 million</td></tr></tbody></table> <!-- /wp:shortcode --> <!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/global-number-of-missing-women?time=earliest..2015" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":4} --> <h4>How many girls and women are missing every year?</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Above are estimates of the total number of missing women in the world. But how many are 'missing' each year?</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In this chart we see estimates of (1) the number of 'missing' female births from prenatal sex discrimination; and (2) excess female deaths as a result of postnatal discrimination.{ref}Bongaarts, J., &amp; Guilmoto, C. Z. (2015). <a rel="noreferrer noopener" href="https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=doi.org%2F10.1111%2Fj.1728-4457.2015.00046.x&amp;btnG=" target="_blank">How many more missing women? Excess female mortality and prenatal sex selection, 1970–2050</a>. Population and Development Review, 41(2), 241-269.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>3.3 million women is the estimate fo 2015 – approximately half of which were missing births and half of which are attributed to excess female mortality. After the 1970s sex-selective abortions (shown as missing births) became more common. Until 1980, nearly all missing women were the result of excess female mortality; by 2015 as many were from missing births each year.</p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe style="width: 100%; height: 600px; border: 0px none;" src="https://ourworldindata.org/grapher/missing-female-births-and-excess-mortality"></iframe> <!-- /wp:html --> <!-- wp:heading --> <h2>Why is there a preference for a son in some places?</h2> <!-- /wp:heading --> <!-- wp:paragraph --> <p>In countries where there is a clear imbalance in sex ratio, there's preference for a boy. But why does this preference exist?</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Son preference is most common in countries across East and South Asia, but also in some countries in the Middle East and North Africa.{ref}Hesketh, T., Lu, L., &amp; Xing, Z. W. (2011). <a href="http://www.cmaj.ca/content/183/12/1374">The consequences of son preference and sex-selective abortion in China and other Asian countries</a>. <em>CMAJ</em>, 183(12), 1374-1377.{/ref} Although there are significant cultural, economic and societal differences between these countries there are important parallels which explain strong preference for a boy.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>What these countries tend to have in common is a strong logic of 'patrilineality': the logic that productive assets move through the male line within the family.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., &amp; Hwa-Ok, B. (2003). <a href="https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=doi.org%2F10.1080%2F00220380412331293807&amp;btnG=">Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea</a>. <em>The Journal of Development Studies</em>, 40(2), 153-187.{/ref} Although many other countries also have patrilineality to some degree, in countries with a strong preference for a son, researchers find this logic to be much more rigid. The social order of families resides with the males: lineage is passed from father to son. Men within the social order are the fixed points, and women the moving points: when a daughter marries, she leaves the current family to join a new one.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>This can produce&nbsp;economic and social benefits to having a son rather than a daughter, including:</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li><strong><em>Family name</em></strong>: the lineage within a family stays within the male line. Having a son therefore continues the family name.</li><li><strong><em>Old age support</em></strong>: sons within a family are often responsible for supporting parents in illness and old age.{ref}Hesketh, T., Lu, L., &amp; Xing, Z. W. (2011). <a href="http://www.cmaj.ca/content/183/12/1374">The consequences of son preference and sex-selective abortion in China and other Asian countries</a>. <em>CMAJ</em>, 183(12), 1374-1377.{/ref} Elderly parents often live with married children and overwhelmingly so with their sons. This provides a strong economic incentive for a son for old age support. It's a key differentiating factor between countries with and without strong son preference: in Taiwan, it's rare for parents to live with a married daughter, but in the Philippines (without strong son preference) parents are equally likely to live with the son or daughter.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., &amp; Hwa-Ok, B. (2003). <a href="https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=doi.org%2F10.1080%2F00220380412331293807&amp;btnG=">Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea</a>. <em>The Journal of Development Studies</em>, 40(2), 153-187.{/ref}</li><li><strong><em>Dowries</em></strong>: a dowry – the transfer of property or money from the bride's to the groom's family – is an important economic concern for having a daughter. Studies in India have suggested that a dowry is the most common reason for not wanting a girl.{ref}Diamond‐Smith, N., Luke, N., &amp; McGarvey, S. (2008). <a href="https://www.tandfonline.com/doi/full/10.1080/13691050802061665">‘Too many girls, too much dowry’: son preference and daughter aversion in rural Tamil Nadu, India</a>. <em>Culture, Health &amp; Sexuality</em>, 10(7), 697-708.{/ref} Even when parents themselves didn't have a dowry in their own marriage, many carry the expectation of having to provide one for a daughter, or asking for one from a future daughter-in-law. </li><li><strong><em>Labor force opportunities</em></strong>: males can bring better economic opportunities for a family. This can be the result of real sex differences in economic opportunities, but also results from undervaluing the work of women. In many countries, unpaid or informal work <a href="https://ourworldindata.org/female-labor-supply#informal-work-unpaid-care-work">accounts for a majority share</a> of female employment. In this sense, informal employment is often seen simply as an extension of a women's domestic work rather than being valued in its own right.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., &amp; Hwa-Ok, B. (2003). <a href="https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=doi.org%2F10.1080%2F00220380412331293807&amp;btnG=">Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea</a>. <em>The Journal of Development Studies</em>, 40(2), 153-187.{/ref}</li><li><strong><em>Family and societal pressure</em></strong>: it's not just economic concerns that parents worry about: surveys also reveal persistent pressures from family members and communities. In interviews, women often note pressures from female in-laws and husbands, verbal and physical abuse when they didn't produce a son or were pregnant with a girl.{ref}Puri, S., Adams, V., Ivey, S., &amp; Nachtigall, R. D. (2011). <a href="https://www.sciencedirect.com/science/article/pii/S0277953611000700">“There is such a thing as too many daughters, but not too many sons”: A qualitative study of son preference and fetal sex selection among Indian immigrants in the United States</a>. <em>Social Science &amp; Medicine</em>, 72(7), 1169-1176.{/ref}</li><li><strong><em>Religion</em></strong>: in some cultures it's believed that only a son can light the funeral pyre and carry out death-related rites and rituals needed for salvation.{ref}Tandon, S. L., &amp; Sharma, R. (2006). <a href="https://www.sascv.org/ijcjs/snehlata.pdf">Female Foeticide and Infanticide in India: An Analysis of Crimes against Girl Children</a>. <em>International Journal of Criminal Justice Sciences</em>, 1(1).{/ref}</li></ul> <!-- /wp:list --> <!-- wp:heading --> <h2>What are the consequences of a skewed sex ratio?</h2> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Across several countries in Asia, and North Africa we see highly skewed sex ratios in favour of males. Strong preference for sons has led to an increasing number of "missing women" and therefore an "excess of males".</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>There are a number of adverse consequences which could result from highly imbalanced numbers of men and women in society. These present a risk to men, women, family structures and society as a whole.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The obvious consequence of gender imbalance is a large number of unmarriageable men.{ref}Hesketh, T. (2011). <a href="https://www.sciencedirect.com/science/article/pii/S0378378211002763">Selecting sex: The effect of preferring sons</a>. <em>Early Human Development</em>, 87(11), 759-761.{/ref} A lack of women of marriageable age could have several impacts on marriage dynamics for men:{ref}Guilmoto, C. Z. (2007). <a href="https://pdfs.semanticscholar.org/b1e7/3587d7bce7cec908286fba3f3c0b32257566.pdf">Sex-ratio imbalance in Asia: Trends, consequences and policy responses</a>. <em>Paris: LPED/IRD</em>.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li>many men will have to delay marriage;</li><li>this will have a knock-on impact on younger men: not only will they be impacted by a skewed sex ratio for their generation, but will also have a 'backlog' of men from the previous generation in the 'marriage market';</li><li>a significant number of men will have to forego marriage altogether;</li><li>the poorest men will likely be most highly impacted by this – it's hypothesised that women will "marry up" in society, leaving the men with least resources disproportionately affected;</li><li>one of the most common reasons for son preference is for family lineage (the passing down of the family name through males in the family) – this will likely not occur in families where sons do not marry.</li></ul> <!-- /wp:list --> <!-- wp:paragraph --> <p>Whilst we might assume that this dynamic would favour women, they could also suffer negative consequences:</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li>a women's value may be increasingly lie in her role as a wife, daughter-in-law or mother. This may deny her alternative pathways, such as remaining single or becoming more career-oriented;</li><li>women may feel increased pressure or incentives to marry or have children earlier in life (possibly closing off different economic or labour opportunities);</li><li>women may be at increased risk of violence (emotional, sexual or physical) or trafficking.{ref}Hudson, V. M., &amp; Den Boer, A. (2005). <a href="https://kar.kent.ac.uk/11409/1/WW-missingwomen-05.pdf">Missing women and bare branches: gender balance and conflict</a>. <em>Environmental Change and Security Program Report</em>, (11), 20-24.{/ref}</li></ul> <!-- /wp:list --> <!-- wp:paragraph --> <p>Imbalanced gender ratios could have negative consequences for both men and women. For society more broadly, there are several hypotheses that it will also result in more crime, violence and disorder in communities. The rationale being that not only will there be an excess of men who do not marry and have their own family, but that the most affected will be those of lowest socioeconomic status, the most uneducated and with fewer opportunities.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Hudson and De Boer (2004) propose that this situation will result in significant social stability and security concerns.{ref}Hudson, V. M., &amp; Den Boer, A. (2005). <a href="https://kar.kent.ac.uk/11409/1/WW-missingwomen-05.pdf">Missing women and bare branches: gender balance and conflict</a>. <em>Environmental Change and Security Program Report</em>, (11), 20-24.{/ref} Although studies have found correlation between the prevalence of violence and more imbalanced gender ratios, it's difficult to disentangle a causal effect.{ref}Diamond-Smith, N., &amp; Rudolph, K. (2018). <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0197516">The association between uneven sex ratios and violence: Evidence from 6 Asian countries</a>. <em>PLoS One</em>, 13(6), e0197516.{/ref} Other researchers suggest that the evidence does not support this concern: that rather than showing through aggression and violence, excluded men will be more marginalised, lonely and at risk of psychological problems.{ref}Hesketh, T. (2011). <a href="https://www.sciencedirect.com/science/article/pii/S0378378211002763">Selecting sex: The effect of preferring sons</a>. <em>Early Human Development</em>, 87(11), 759-761.{/ref} What's clear is that the persistence of imbalanced sex ratios means there will be demographic consequences for many decades to come.</p> <!-- /wp:paragraph --> <!-- wp:heading --> <h2>What affects the strength of gender bias?</h2> <!-- /wp:heading --> <!-- wp:heading {"level":3} --> <h3>Are richer and more educated parents less likely to have gender preference?</h3> <!-- /wp:heading --> <!-- wp:paragraph --> <p>If our aim is to address the issue of a skewed sex ratio and female discrimination, an obvious question to ask is: will development fix the problem? Is it the case that son preference is restricted to those at lower incomes, therefore the problem disappear if <a href="https://owid.cloud/extreme-poverty">poverty</a> falls and societies develop?</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The evidence to date suggests, no: development on its own does not address it.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Studies which have looked in detail at the extent of sex ratio imbalances by demographic (comparing income level, education, literacy, employment factors amongst others) often conclude the opposite: that richer, urban families tend to discriminate more than the poor.{ref}Filmer, D., Friedman, J., &amp; Schady, N. (2008). <a href="https://elibrary.worldbank.org/doi/abs/10.1596/1813-9450-4716">Development, modernization, and son preference in fertility decisions</a>. <em>The World Bank</em>.{/ref} For example, in North India higher castes (who tend to be richer) had more skewed sex ratios than lower castes.{ref}Gupta, M. D. (1987). <a href="https://www.jstor.org/stable/1972121">Selective discrimination against female children in rural Punjab, India</a>. <em>Population and Development Review</em>, 13(1), 77-100.{/ref} Narrowing in on specific districts and household in India and South Korea suggested that it is richer families who show greater discrimination.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., &amp; Hwa-Ok, B. (2003). <a href="https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=doi.org%2F10.1080%2F00220380412331293807&amp;btnG=">Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea</a>. <em>The Journal of Development Studies</em>, 40(2), 153-187.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Despite rising incomes and development across many countries in Asia, North Africa and Eastern Europe, the sex ratio got worse, not better. An important driver which may link the increase in sex ratio with development and rising incomes is fertility rates. As we show in our entry on <a href="https://owid.cloud/fertility-rate">fertility rates</a>, there is a very strong impact of improving development and falling fertility. And falling fertility rates in turn play a key role in exacerbating gender preference. This is often called the 'fertility squeeze'.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><strong>In smaller families, you're less likely to have a son by chance</strong></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Imagine you have five or six children: there's a very high chance that at least one of them will be a boy. For five children, there's around a 98% chance you'll have a son.{ref}To calculate this, we need to calculate the probability that in having 5 children, we have five girls. Because the 'natural' sex ratio at birth is around 105 boys per 100 girls, the probability of having a girl at each birth is slightly lower than half: it's around 47.6%. To calculate the probability of having 5 girls, we then do 0.476^5 = 0.0245 [or 2.45%]. The probability that you have at least one boy is therefore 100% - 2.45% = 97.6%.{/ref} Now imagine you have only one or two children: the likelihood you have a son is much smaller. If you have only one child, you're chances of having a son are just over half (52%); if you have two children, the odds are 77%.{ref}Since the 'natural' sex ratio at birth is around 105 boys per 100 girls, the odds of having a boy are slightly higher than having a girl: 52%. To calculate the odds of having a boy when you have two children, we start by calculating the probability of having two girls. The probability of having a girl at each birth is 47.6% [100/105 * 100]. The probability of two births producing two girls is then calculated as 0.476^2 = 0.227 [22.7%]. The odds that one is a boy is therefore 100% - 22.7% = 77%.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In many countries across the world, this <a href="https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=CHN+IND+KOR">transition happened</a>: in India, average fertility rates <a href="https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=IND">fell from almost 6 to 2 children per woman</a>; in China from over <a href="https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=CHN">6 down to 1.2 children</a>; in South Korea from over <a href="https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=KOR">6 to just under one child per woman</a>. As countries got richer; education levels increased; women gained more rights to education labour participation and healthcare decisions; fertility rates fell rapidly.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>But the result is that if you really want a son, your chances of having one naturally are now much lower. For parents of fewer children with a strong son preference, a sex-selective abortion becomes therefore a much more important option.</p> <!-- /wp:paragraph --> <!-- wp:heading {"level":4} --> <h4>Evidence from India</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Seema Jayachandran (2017) tried to quantify how much of the skew in sex ratio in India might be attributed to the decline of the fertility rate in the country.{ref}Jayachandran, S. (2017). <a href="https://pubs.aeaweb.org/doi/pdfplus/10.1257/app.20150576">Fertility decline and missing women</a>. <em>American Economic Journal: Applied Economics</em>, 9(1), 118-39.{/ref} In this visualization we summarize results from this research, through three charts:</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li><strong>Left chart</strong>: we see the percentage of respondents of a survey in India who said they would prefer a son when given a hypothetical family size (number of children) from one to five i.e. having only one child; two children etc.{ref}The survey was actually posed to mothers and fathers of what they would want for their own children (who were all in secondary school at the time of the of survey). Asking it of a future hypothetical scenario helps to avoid hindsight bias.{/ref} Here we see that if they were having only one child, more than 80% of both mothers and fathers would prefer a son. This preference rapidly declines when they are asked about additional children; in fact, in the scenarios in which parents already have some sons parents preferred to have daughters.{ref}The reason for a switch to daughters is not totally clear. It's suggested having daughters within larger families is preferred to provide care for others in the family and the household. It may also be the case that a larger number of sons creates tension and conflict with regards to resource allocation.{/ref} These results suggest that parents have a very strong preference to have a son if they have a small family.</li><li><strong>Middle chart</strong>: in red we see that the <em>desired fertility rate</em> – the number of children a woman desires to have – has declined in India in recent decades. At the same time, the child sex ratio – the number of males per 100 females – increased. The dashed line here shows the estimated change in sex ratio which results from falling fertility rates alone.</li><li><strong>Right chart</strong>: the blue line shows how the child sex ratio has increased over time. Shown in grey is the estimated increase in the sex ratio which can be attributed solely to the decline in fertility rates.</li></ul> <!-- /wp:list --> <!-- wp:paragraph --> <p>Seema Jayachandran (2017) results suggest that between one-third and one-half of the change in sex ratio in India since 1981 can be attributed to the decline in fertility rates. Or in other words: If there had been no change in fertility rates over time, there would still be a skew in the sex ratio. But fertility declines have had a significant impact on exacerbating son preference.</p> <!-- /wp:paragraph --> <!-- wp:image {"align":"center","id":23713,"linkDestination":"custom"} --> <div class="wp-block-image"><figure class="aligncenter"><a href="https://owid.cloud/app/uploads/2019/06/Fertility-impact-on-son-preference.png"><img src="https://owid.cloud/app/uploads/2019/06/Fertility-impact-on-son-preference-800x364.png" alt="" class="wp-image-23713"/></a></figure></div> <!-- /wp:image --> <!-- wp:heading {"level":4} --> <h4>Development drives factors which can both increase and decrease gender preference</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Disentangling a clear relationship between development and changes in the sex ratio is difficult because better education and rising incomes can impact aspects of gender selection in opposing ways.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The reason is that the skewed sex ratio not only the result from the gender preference alone, but crucially also the ability to act upon it – by having a sex-selective abortion, for example. Kashyap and Villavicencio (2016) suggest that sex-selection practices result from three conditions being met:{ref}Kashyap, R., &amp; Villavicencio, F. (2016). <a href="https://link.springer.com/article/10.1007/s13524-016-0500-z">The dynamics of son preference, technology diffusion, and fertility decline underlying distorted sex ratios at birth: A simulation approach</a>. <em>Demography</em>, 53(5), 1261-1281.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:list {"ordered":true} --> <ol><li><em>willingness</em> to consider sex selection because you have a gender preference;</li><li><em>ability</em> to act upon it through access to prenatal sex-determination screening and abortion services;</li><li><em>readiness</em> to act upon it to get the desired sex preferences within the family.</li></ol> <!-- /wp:list --> <!-- wp:paragraph --> <p>How these three conditions change with development, education, and rising incomes can be in conflict. For example, research results suggest that higher education of the parents means a lower preference for a son.{ref}Jayachandran, S. (2017). <a href="https://pubs.aeaweb.org/doi/pdfplus/10.1257/app.20150576">Fertility decline and missing women</a>. <em>American Economic Journal: Applied Economics</em>, 9(1), 118-39.{/ref} But, increased education is also associated with falling fertility rates and this decline in fertility (the 'fertility squeeze') increases son preference, as we explored above. Education therefore has two counteracting effects on the sex ratio: education decreases the <em>willingness</em> for gender preference, but increases the&nbsp;<em>readiness</em> for influencing sex preferences within the family.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Development also affects condition (2): the ability to act upon gender preference. It is often the case that richer, urban families have greater access to technologies which would allow for sex identification during pregnancy, and also a safer abortion. Poorer families in rural areas may not have this opportunity, despite having strong son preference. As they get richer, these opportunities may become available to them.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Kashyap and&nbsp;Villavicencio (2017) tried to model how the changes in&nbsp;<em>willingness</em>,&nbsp;<em>ability</em>, and&nbsp;<em>readiness</em> all affect the change in sex ratio in specific countries.{ref}Kashyap, R., &amp; Villavicencio, F. (2016). <a href="https://link.springer.com/article/10.1007/s13524-016-0500-z">The dynamics of son preference, technology diffusion, and fertility decline underlying distorted sex ratios at birth: A simulation approach</a>. <em>Demography</em>, 53(5), 1261-1281.{/ref} They found that even very low levels of son preference can have a significant impact on the sex ratio if sex-selection technology diffuses steadily and fertility declines quickly. This means that in contexts where economic development is fast – meaning fertility rates fall quickly and prenatal screening technologies become widely accessible – even very small levels of son preference across a population can have a significant impact on the overall sex ratio.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The relationship between development and sex ratio is complex and non-linear: what's clear is that the issue does not quickly disappear through economic development alone.</p> <!-- /wp:paragraph --> <!-- wp:heading {"level":3} --> <h3>Does banning prenatal practices reduce sex-selective abortion?</h3> <!-- /wp:heading --> <!-- wp:paragraph --> <p>One of the three conditions for sex-selection is the <em>ability</em> to act upon gender practices through access to technology.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Prenatal sex selection (PSS) relies on two technologies: prenatal sex determination (the ability to determine the sex of a foetus during pregnancy) and selective abortion.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>This raises the question of whether policies that aim to regulate prenatal sex determination and abortion have an impact on the prevalence of sex selection.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Several governments limited prenatal sex selection through regulation when it became clear that sex selection was common and increasing. South Korea, China and India all implemented sex-selective abortion bans. Were they successful?</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Much of the literature on the topic suggests the bans alone were not effective enough to address the problem.{ref}Gupta, M. D. (2016). <a href="https://paa.confex.com/paa/2016/mediafile/ExtendedAbstract/Paper1728/banning%20prenatal%20sex-selection%20PAA%202016.pdf">Is banning sex-selection the best approach for reducing prenatal discrimination?</a>. In <em>Population Association of America meeting</em>, Washington DC.{/ref}{ref}Subramanian, S. V., &amp; Selvaraj, S. (2009). <a href="https://jech.bmj.com/content/63/3/245.short">Social analysis of sex imbalance in India: before and after the implementation of the Pre-Natal Diagnostic Techniques (PNDT) Act</a>. <em>Journal of Epidemiology &amp; Community Health</em>, 63(3), 245-252.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Looking at how the sex ratio at birth changed pre- and post-ban in each country also does not suggest that they were very effective. <strong>South Korea</strong>&nbsp;enacted a ban on prenatal sex identification in 1987/88. At this point the sex ratio at birth was around 110 male per 100 female births – as we see in the chart here. Following the introduction of the ban, the sex ratio continued to increase – reaching over 115 males per 100 female births in 1990 and maintaining a high ratio through the early 1990s.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>For <strong>China</strong> the evidence is similar.&nbsp;in 1994 – as part of its Law on Maternal and Infant Health Care – China introduced a ban of prenatal sex determination. As we see in this chart, the sex ratio at birth continued to increase after the introduction of the ban. In 1993 the ratio was 114 male per 100 female births; by the early 2000s this had increased to 118:100.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><strong>India&nbsp;</strong>introduced the Pre-Conception and Pre-Natal Diagnostic Techniques Act (PNDT) in 1994 which prohibited sex selection practices, including pre-screening to determine the sex of a fetus. In the decade which followed the introduction of the act, the sex ratio at birth did not improve.</p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe style="width: 100%; height: 600px; border: 0px none;" src="https://ourworldindata.org/grapher/sex-ratio-at-birth-males-chao-et-al"></iframe> <!-- /wp:html --> <!-- wp:paragraph --> <p>At first glance, this would suggest that the banning of sex-selection practices was unsuccessful. The sex ratio continued to increase after their implementation.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Whilst researchers agree that bans alone were not effective enough to stop the practice, many acknowledge that we don't know the counterfactual scenario without a ban.{ref}Gupta, M. D. (2016). Is banning sex-selection the best approach for reducing prenatal discrimination?. In <em>Population Association of America meeting</em>, Washington DC.{/ref} Without a ban the sex ratio might have increased even further. Some studies have argued that bans were effective in preventing a worsening of gender imbalance, even if they didn't reduce it.{ref}Nandi, A., &amp; Deolalikar, A. B. (2013). Does a legal ban on sex-selective abortions improve child sex ratios? Evidence from a policy change in India. Journal of Development Economics, 103, 216-228.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>These policies may have had some impact on reducing the increase, but they clearly did not come close to ending the practice.<!----------------------------------><!----------------------------------><!----------------------------------><!----------------------------------></p> <!-- /wp:paragraph --> <!-- wp:heading --> <h2>Definitions</h2> <!-- /wp:heading --> <!-- wp:paragraph --> <p><strong>Sex ratio at birth</strong>: the number of males born per 100 females.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><strong>'Expected' sex ratio at birth</strong>: the expected sex ratio at birth is not completely equal: under ordinary circumstances we would expect there to be slightly more boys born than girls. This means that in all countries, births are male-biased. The <strong>expected sex ratio is approximately 105 boys born per 100 girls</strong>. This is the <a href="http://www.searo.who.int/entity/health_situation_trends/data/chi/sex-ratio/en/">'natural' sex ratio reported by the World Health Organization</a> (WHO). There can be some variability in this expected ratio, ranging from around 102 to 107 boys per 100 girls. Having a male-biased sex ratio at birth therefore doesn't necessarily represent gender discrimination, although much more skewed ratios (above 107 boys per 100 girls) does suggest the use of gender selection practices.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><strong>Prenatal sex selection</strong>: prenatal sex selection practices are those which are used to discriminate based on gender <em>during a woman's pregnancy</em>. This requires the use of prenatal screening practices which can determine the sex of the fetus – this is often referred to as <strong>prenatal detection (PD)</strong>. This is followed by abortion in the case that it isn't the desired sex.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><strong>Postnatal sex selection</strong>: postnatal sex selection is the discrimination based on gender&nbsp;<em>after the child has been born</em>. Postnatal sex selection can occur either directly through selective infanticide, or indirectly from the premature death of girls due to maltreatment, neglect or unequal treatment.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><strong>Infanticide</strong>:&nbsp;infanticide&nbsp;(or infant homicide) is the intentional killing of infants.</p> <!-- /wp:paragraph --> <!-- wp:heading --> <h2>Data Sources</h2> <!-- /wp:heading --> <!-- wp:heading {"level":4} --> <h4>World Bank</h4> <!-- /wp:heading --> <!-- wp:list --> <ul><li><strong>Data Source:</strong> World Bank – World Development Indicators</li><li><strong>Description of available measures:</strong> <ul> <li>Population female (% of total)</li> <li>Sex ratio at birth</li> <li>Child mortality, by sex</li> </ul> </li><li><strong>Time span:</strong> 1962-2017</li><li><strong>Geographical coverage:</strong> Global, by country</li><li><strong>Link:</strong>&nbsp;<a href="http://data.worldbank.org/data-catalog/world-development-indicators">http://data.worldbank.org/data-catalog/world-development-indicators</a></li></ul> <!-- /wp:list --> <!-- wp:heading {"level":4} --> <h4>Chao et al. (2019)</h4> <!-- /wp:heading --> <!-- wp:list --> <ul><li><strong>Data Source:</strong> Chao, F., Gerland, P., Cook, A.R., Alkema, L. (2019). Systematic assessment of the sex ratio at birth for all countries and estimation of national imbalances and regional reference levels. <em>PNAS</em>.</li><li><strong>Description of available measures:</strong> <ul> <li>Sex ratio at birth (modelled estimates)</li> </ul> </li><li><strong>Time span:</strong> 1950-2017</li><li><strong>Geographical coverage:</strong> Global, by country</li><li><strong>Link:</strong>&nbsp;<a href="https://www.pnas.org/content/early/2019/04/09/1812593116">https://www.pnas.org/content/early/2019/04/09/1812593116</a></li></ul> <!-- /wp:list --> 
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                        "text": "This article was first published in June 2019.",
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                        "text": "The ratio between the number of males and females in a society is referred to as the gender ratio. This ratio is not stable but instead shaped by biological, social, technological, cultural, and economic forces. And in turn the gender ratio itself has an impact on society, demography, and the economy.",
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                        "text": "In this entry we provide an overview of the variation and the changes of the gender ratio across the world. We study how it changes from birth to late life; the forces that change the ratio of men to women.",
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                        "text": "Many argue persuasively that the terms 'gender' and 'sex' are not to be used interchangeably.{ref}Pryzgoda, J., & Chrisler, J. C. (2000). Definitions of gender and sex: The subtleties of meaning.\u00a0",
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                        "children": [
                            {
                                "text": "Sex Roles",
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                        "text": ",\u00a0",
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                        "children": [
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                                "text": "43",
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                    },
                    {
                        "text": "(7-8), 553-569.{/ref}",
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                        "text": " In this context here we have however decided to make an exception: we speak of the 'gender ratio' because it's the established term and it will help all those who want to be informed about this topic and search this term. But we also speak of the 'sex ratio' because this is arguably the more accurate term and it is increasingly used within the academic literature.",
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                        "slug": "sex-ratio-at-birth",
                        "text": "The sex ratio at birth is not equal: in every country births are male-biased. There are biological reasons why there are slightly more boys born every year than girls. The 'natural' sex ratio at birth is around 105 boys per 100 girls (ranging from around 103 to 107 boys)."
                    },
                    {
                        "slug": "biology-or-discrimination-which-countries-have-skewed-sex-ratios-at-birth",
                        "text": "In some countries, the sex ratio at birth is much more skewed than would occur naturally. Today and in the recent past this is particularly common across Asia and North Africa. Here there is clear evidence of gender selection through prenatal sex determination and selective abortion."
                    },
                    {
                        "slug": "how-does-sex-ratio-vary-with-birth-order",
                        "text": "In countries where there is a clear son preference, the sex ratio at birth becomes increasingly skewed with birth order (the third or fourth born children are more likely to be boys than the first or second child)."
                    },
                    {
                        "slug": "sex-ratio-in-childhood",
                        "text": "In nearly every country, boys are more likely to die in childhood than girls. There are biological reasons for this: boys are more susceptible to birth complications and infectious diseases."
                    },
                    {
                        "slug": "infanticide-and-excess-female-mortality",
                        "text": "In countries where there is strong son preference, mortality rates for girls are higher than would be expected: this can occur either through direct infanticide, but also through neglect and unequal treatment."
                    },
                    {
                        "slug": "sex-ratio-through-adulthood",
                        "text": "The sex ratio tends to decrease\u00a0over the life course (from becoming male-biased to female-biased). This is because women tend to live longer than men."
                    },
                    {
                        "slug": "how-many-missing-women-are-there",
                        "text": "It's estimated that today there are over 130 million 'missing women' in the world as a result of selective abortion and excess female deaths."
                    },
                    {
                        "slug": "does-banning-prenatal-practices-reduce-sex-selective-abortion",
                        "text": "The banning of sex determination scanning and gender-selective abortion may have limited the increase in sex ratio at birth in some countries, but did not fully address the problem."
                    },
                    {
                        "slug": "do-richer-and-more-educated-parents-have-less-gender-bias",
                        "text": "Development can have opposing impacts on sex ratio: there is evidence that the son preference declines with education, but this often goes hand-in-hand with declining fertility rates and increased access to selective technologies (which can increase the sex ratio)."
                    }
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                        "children": [
                            {
                                "url": "#all-charts",
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                                    {
                                        "text": "See all interactive charts on gender ratio \u2193",
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                "type": "horizontal-rule",
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                "text": [
                    {
                        "text": "Gender Ratio across the world",
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                "level": 1,
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                "text": [
                    {
                        "text": "What share of the population is male and female?",
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                "level": 2,
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                "value": [
                    {
                        "text": "The sex ratio \u2013 the share of the population that is female \u2013 varies across the world. And globally in 2020 the share of women in the world was just under 50%.",
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                "value": [
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                        "text": "There are three reasons why the sex ratio of populations varies and is rarely equal:",
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                        "value": [
                            {
                                "text": "differences in mortality rates and life expectancy for women and men. Women, on average, ",
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                            },
                            {
                                "url": "https://owid.cloud/why-do-women-live-longer-than-men",
                                "children": [
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                                        "text": "live longer than men",
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                            {
                                "text": ". This means that all else being equal, we would expect females to account for slightly more than half of the total population.",
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                        "type": "text",
                        "value": [
                            {
                                "text": "sex ratios at birth are not equal. In all countries, there are more male than female births (the extent of which varies by country as we will see below). This means that all else being equal, we would expect males to account for slightly more than half of the total population.",
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                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "migration can also affect the sex ratio of the population. If in some countries there is a significant amount of imported male-dominant labour, all else being equal, we would expect males to account for more than half of the total population.",
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                "value": [
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                        "text": "The magnitude and balance of these factors determines the sex ratio of the total population.",
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                "value": [
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                        "text": "In the map we see the sex ratio of populations: this is shown as the percentage of the total population which is female. Countries over 50 percent (shown in blue) have more females than males; those below 50 percent (shown in red) have fewer females.",
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                "value": [
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                        "text": "Most countries have a female share of the population between 49 and 51 percent (within one percentage point of parity).",
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                "value": [
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                        "text": "There are however a few notable outliers:",
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                                "text": "across several countries in South and East Asia \u2013 most notably India and China \u2013 there are significantly fewer females than males. These are countries where there are large differences in sex ratio at birth.",
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                        "value": [
                            {
                                "text": "in several countries across the Middle East there are many more males than females: in Oman, women are outnumbered 3-to-1; in the United Arab Emirates (UAE) it's almost 4-to-1. If we look at how this has changed over time (click on the country to see this), we see the share of the population that is female has declined from a ratio close to parity decades ago. The primary reason for this is a large male migrant stock: in 2017, 45 percent of the Oman and 88 percent of the UAE population were from immigration.{ref}United Nations, Department of Economic and Social Affairs, Population Division (2017). ",
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                            },
                            {
                                "url": "http://www.un.org/en/development/desa/population/migration/publications/migrationreport/docs/MigrationReport2017_Highlights.pdf",
                                "children": [
                                    {
                                        "text": "International Migration Report 2017",
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                                "spanType": "span-link"
                            },
                            {
                                "text": "\u00a0(ST/ESA/SER.A/403).{/ref} The UN reports that only 16 and 25 percent of international migrants to Oman and UAE, respectively, were female. ",
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                        "value": [
                            {
                                "text": "there are significantly more females than males in Eastern Europe. Populations in Eastern Europe have some of the largest gaps in life expectancy between men and women: in Russia in 2021, for example, the life expectancy at birth for men was only around 64 years compared to around 75 years for women.",
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                "url": "https://ourworldindata.org/grapher/share-population-female",
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                "type": "horizontal-rule",
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            {
                "text": [
                    {
                        "text": "Gender Ratio at birth and through the life course",
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                "level": 1,
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                "text": [
                    {
                        "text": "How does the sex ratio at birth vary across the world?",
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                "level": 2,
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                "value": [
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                        "text": "Across the world there are differences in the sex ratio at different life stages. This imbalance in the male and female population can in some cases be traced back to birth: in some countries the number of boys and girls born each year is significantly skewed.",
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                "value": [
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                        "text": "In the map we see the differences in sex ratio at birth across the world. Here the sex ratio is measured as the number of male births for every 100 female births; a value greater than 100 indicates there are more boys than girls born that year. A figure of 110 would indicate that there are 110 male births for every 100 female births.",
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                        "text": "The first striking point is that in every single country of the world there are more boys born than girls. This has been true for all years for which we have data (as far back as 1950) in all countries of the world, as you can when you move the timeslider below the map further back.",
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                        "text": "Does this mean every country selects for boys prior to birth; for example, through induced abortion practices which preferentially select for boys? Not necessarily.",
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                "value": [
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                        "text": "In the absence of selective abortion practices, births in a given population are typically male-biased \u2013 the chances of having a boy are very slightly higher than having a girl.",
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                ],
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                "url": "https://ourworldindata.org/grapher/sex-ratio-at-birth",
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                "text": [
                    {
                        "text": "Why are births naturally expected to be male-biased?",
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                        "text": "For most countries, there are around 105 males per 100 female births. This is what the World Health Organization (WHO) estimates as\u00a0the ",
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                                "text": "'expected' sex ratio",
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                        "text": " at birth: in the absence of gender discrimination or interference we'd expect there to be around 105 boys born per 100 girls, although this can range from around 103 to 107 boys per 100 girls.\u00a0Why is this?",
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                        "text": "In the most comprehensive study of its kind, Orzack et al. (2015) monitored the trajectory of sex ratio from conception through to birth across five different methods.{ref}Orzack, S. H., Stubblefield, J. W., Akmaev, V. R., Colls, P., Munn\u00e9, S., Scholl, T., \u2026 & Zuckerman, J. E. (2015). ",
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                        "url": "https://pdfs.semanticscholar.org/3986/f62b66ee8450859909e122fb2974c1c9fe6b.pdf",
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                                "text": "The human sex ratio from conception to birth",
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                        "text": ". ",
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                        "children": [
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                                "text": "Proceedings of the National Academy of Sciences",
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                        "text": ", 112(16), E2102-E2111.{/ref}",
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                        "text": " This produced the largest dataset available on the sex ratio throughout the stages of pregnancy.",
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                        "text": "A key result from this study was that the sex ratio at conception is equal: there is no difference in the number of males and females conceived. For births to be consistently male-biased, there must be gender differences in the probability of miscarriage through pregnancy.",
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                        "text": "The study found that although the probability of miscarriage varies between genders across the course of a pregnancy, female mortality is slightly higher than male mortality over the full period:",
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                                "text": "there is a higher probability that an embryo with chromosomal abnormalities{ref}In the paper the authors differentiate between 'karyotypically normal' and 'karyotypically abnormal'. This refers to whether there are mutations in chromosomes, such as an extra, missing or irregular portion of chromosomal DNA. 'karyotypically abnormal' embryos have a lower probability of surviving to birth, or often lead to other human diseases/conditions.{/ref} is male \u2013 in the first week of pregnancy, excess male mortality therefore means pregnancy is female-biased;",
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                        "value": [
                            {
                                "text": "in the next 10-15 weeks of pregnancy female mortality is higher, which increases the ratio in favor of males;",
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                        "value": [
                            {
                                "text": "male and female mortality is approximately equal around week 20;",
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                                "text": "between weeks 28-35 of pregnancy, there is higher male mortality.",
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                        "text": "Overall, a male-biased sex ratio at birth is the result.",
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                "text": [
                    {
                        "text": "In some countries the sex ratio is skewed beyond the expected sex ratio",
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                        "text": "Some male-bias in births is what we expect with no deliberate gender selection through parents or society more broadly. There are, however, some key outliers in the world today: in countries including China, India, Vietnam, Pakistan, and Azerbaijan this ratio is very skewed. Here it's likely that deliberate selection practices explain part of the high sex ratio as we explore ",
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                                "url": "https://ourworldindata.org/gender-ratio#biology-or-discrimination-which-countries-have-skewed-sex-ratios-at-birth",
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                                        "text": "here",
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                        "text": ".",
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                "text": [
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                        "text": "The sex ratio varies with birth order",
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                        "text": "Most countries have a ",
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                        "url": "https://ourworldindata.org/gender-ratio#sex-ratio-at-birth",
                        "children": [
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                                "text": "sex ratio at birth",
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                        "text": " which is around the ",
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                                "text": "expected range of 105 boys born for every 100 girls",
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                    {
                        "text": ".\u00a0There are exceptions to this: there are countries \u2013 most notably in Asia \u2013 with highly skewed sex ratios in favor of males.",
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                        "text": "The preference in some countries for a son is seen in the overall sex ratio at birth figures above. But this bias is even stronger when we look at how this ratio is affected by the birth order of children.",
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                        "text": "In this visualization we look at the case of India and how sex ratios change from the 1st child in a family through to the 2nd, 3rd, 4th, and 5th born children. This is adapted from the\u00a0",
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                        "children": [
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                                "text": "Economic Survey 2018",
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                        "text": "{ref}Jaitley, A. (2018). ",
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                        "children": [
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                                "url": "https://ideas.repec.org/p/ess/wpaper/id12445.html",
                                "children": [
                                    {
                                        "text": "Economic Survey 2017-18: Volume I, Chapter 7: Gender and Son Meta-Preference: Is Development Itself an Antidote?",
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                                    }
                                ],
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                        "text": "{/ref} and based on data from the DHS and National Family Health Surveys in India. It presents this data in two cases:",
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                                "text": "when the child ",
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                                        "text": "is not",
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                                "text": " the last child born (i.e. the parents have additional children afterwards) \u2013 this is shown in the charts on the left;",
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                                "text": " the last child born in the family (i.e. the parents stop having children afterwards) \u2013 this is shown on the right.",
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                        "text": "Let's first focus on the top row, which presents the data for India as a whole. On the left-hand side we have the sex ratio at birth when the child ",
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                                "text": "is not",
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                        "text": " the last. For the 1st children, the sex ratio is very close to what we would expect 'naturally': a ratio of around 105 boys per 100 girls. But we see that for the 2nd, 3rd, 4th and 5th born children, this ratio is skewed towards girls. Remember again that this is the case when it's not the last child i.e. the parents go on to have another. In other words this shows us that when a girl is born, parents are more likely to have another child. It is evidence that parents are continuing to have children until they get a son.",
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                        "text": "Compare this to the right-hand side where we see the sex ratio when the child ",
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                                "text": "is",
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                        "text": " the last. These ratios are much more skewed towards boys. Parents whose 1st child is a son are much more likely to stop having children. The sex ratio here is 182 boys per 100 girls. This is consistent across the birth order: whether it's the 2nd, 3rd, 4th or 5th child, a family is much more likely to stop having children when they have a boy.",
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                        "text": "Combined we see a strong preference for a son in India: parents are more likely to continue having more children when the child is a girl and they are more likely to stop having children when they have a boy.",
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                        "text": "Now compare these ratios to that of Indonesia in the second row below. Sex ratios here do not diverge strongly from the expected ratio of 105, and there is no clear difference when the child is or isn't the last to be born.\u00a0Parental choices do not point to a strong preference for a son or a daughter.",
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                        "text": "In the third row we see that within India there are large differences in son preference across different states. The data shows that there are states with 'weaker' and 'stronger' preference for a son.",
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                "text": [
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                        "text": "Sex selection practices also became more prominent for later births",
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                "level": 3,
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                        "text": "From the study presented above we see that the sex of a child can, in some countries, be an important deciding factor for when parents stop having children.",
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                        "text": "But birth order also influences the likelihood of prenatal sex selection (PSS) i.e. sex-selective abortion. We see evidence of this across several countries.",
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                        "text": "Researchers looked at Indian national survey data from 1976 to 2005 to see how the sex of children and birth order affects the use of prenatal selection.{ref}Gellatly, C., & Petrie, M. (2017). ",
                        "spanType": "span-simple-text"
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                        "url": "https://jech.bmj.com/content/71/3/269",
                        "children": [
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                                "text": "Prenatal sex selection and female infant mortality are more common in India after firstborn and second-born daughters",
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                    {
                        "text": ". ",
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                    {
                        "children": [
                            {
                                "text": "Journal of Epidemiology & Community Health",
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                    {
                        "text": ", 71(3), 269-274.{/ref} They found a significant and increasing skew in the sex ratio since the 1980s \u2013 a time when the ",
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                    {
                        "url": "https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=IND",
                        "children": [
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                                "text": "average woman in India had five children",
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                        "text": ". This was mainly a result of male selection for the 2nd or 3rd child within a family.\u00a0When the firstborn or the first- and second-born siblings were female then a boy was much more likely the 2nd or 3rd child. This skewed ratio can only be explained from prenatal sex selection in favor of boys.",
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                        "text": "At a local level, a study of a large Delhi hospital known for maternal care showed very similar results.{ref}Manchanda, S., Saikia, B., Gupta, N., Chowdhary, S., & Puliyel, J. M. (2011). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0020097",
                        "children": [
                            {
                                "text": "Sex ratio at birth in India, its relation to birth order, sex of previous children and use of indigenous medicine",
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                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
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                    {
                        "children": [
                            {
                                "text": "PLoS One",
                                "spanType": "span-simple-text"
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                        "text": ", 6(6), e20097. {/ref} The overall sex ratio was male-biased with only 806 girls per 1000 boys. But this got significantly worse when the family already had a daughter: 720 girls per 1000 boys if there was one previous girl and only 178 girls per 1000 boys for two previous daughters. Even for women who had not practiced sex-selection abortion, more mothers who had previously had a girl reported taking traditional medicines (which were ineffective) for sex selection purposes.",
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                        "text": "These examples are of course not restricted to India. Many countries across Asia in particular have similar findings. In this chart we see how the sex ratio in South Korea was affected by birth order. Here we see a very steep rise in the sex ratio of third-, fourth- and later children through the 1980s. By the early 1990s there were more than 200 boys per 100 girls for third-born children; for fourth-born or higher, the ratio was close to 250:100. This occurred at a time the ",
                        "spanType": "span-simple-text"
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                    {
                        "url": "https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=KOR",
                        "children": [
                            {
                                "text": "number of children per woman was falling quickly",
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                    {
                        "text": ": in 1970 its fertility rate was 4.3 children per woman; by 1990 this had fallen to 1.6. South Korea's sex ratio has fallen back to close to natural levels over the past few decades.",
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                        "text": "You can also view the data for China, by using the \"change country\" button in the top-left of the chart. Clearly sex ratios in China have also been affected by birth order.{ref}Jiang, Q., Yu, Q., Yang, S., & S\u00e1nchez-Barricarte, J. J. (2017). ",
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                    {
                        "url": "https://www.cambridge.org/core/services/aop-cambridge-core/content/view/51D48C611E5176A042FF28684041D997/S0021932016000547a.pdf/changes_in_sex_ratio_at_birth_in_china_a_decomposition_by_birth_order.pdf",
                        "children": [
                            {
                                "text": "Changes in sex ratio at birth in china: a decomposition by birth order",
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                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "Journal of Biosocial Science",
                                "spanType": "span-simple-text"
                            }
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                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 49(6), 826-841.{/ref} Here we see that since 1980 \u2013a period in the middle of a rapid ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=CHN",
                        "children": [
                            {
                                "text": "reduction from 4 to 2 children per woman",
                                "spanType": "span-simple-text"
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                        "spanType": "span-link"
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                    {
                        "text": " \u2013 there has been some rise in the male bias for first-born children (rising from the expected 105 boys to 114 boys per 100 girls). But we see a much more significant skew in the ratio for second or third-born children. For third-born children, the ratio was 158 boys per 100 girls, suggesting a high prevalence of sex selection abortions.",
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                        "text": "South Korea provides an important example where the male bias can be successfully addressed. But for several countries across Asia this looks like a major challenge: the data shows that many parents still strongly prefer a son.",
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                ],
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                "url": "https://ourworldindata.org/grapher/sex-ratio-at-birth-by-birth-order",
                "type": "chart",
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                "text": [
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                        "text": "Sex ratio in childhood",
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                "level": 2,
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                        "text": "Sex ratios \u2013 the ratio of males and females \u2013 at birth is male-biased across every country in the world; in ",
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                    {
                        "url": "https://ourworldindata.org/gender-ratio#sex-ratio-at-birth",
                        "children": [
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                                "text": "our section on this",
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                        "text": ", we explain why biologically we'd expect this to be the case. The so-called ",
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                                "text": "'expected' sex ratio at birth",
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                        "text": " was around 105 males per 100 females. But how does this ratio look later in childhood? Does it change from newborns to five-years-olds?",
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                        "text": "In the two charts here we see two perspectives: firstly a global map of the sex ratio at five years old. Just as with the sex ratio at birth, we see the highest ratios in several Asian countries where the share of boys is higher than we would expect. In China, there is close to 115 boys per 100 girls at age five; in India, there are more than 109 boys per 100 girls.",
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                        "text": "Secondly we see a scatterplot comparison of the sex ratio at birth (on the y-axis) versus the ratio at five years old (on the x-axis). The grey line here represents parity: a country which lies along this line has the same ratio at five years old as it does for birth. As we see, most countries lie above this line: this means the sex ratio for newborns is higher than for 5-year-olds.",
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                        "text": "In other words, the male-bias tends to weaken through the first years of childhood. Why is this the case? As we explore in the next section of this entry: across most countries infant and child mortality rates are higher for boys than for girls. This means fewer boys survive the first few years of life. For most countries this results in a decline in the sex ratio.",
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                        "text": "Overall we see that despite higher child mortality in boys, the sex ratio at age five in the majority of countries is over 100: this means boys still outnumber girls in childhood.",
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                "url": "https://ourworldindata.org/grapher/sex-ratio-at-five-years-old",
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                "text": [
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                        "text": "Why do boys die more often than girls?",
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                        "url": "https://ourworldindata.org/mental-health",
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                                "text": " ",
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                                "children": [
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                                        "text": "mental health",
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                                "text": ";",
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                        "url": "https://ourworldindata.org/substance-use",
                        "children": [
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                                "text": " ",
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                                "children": [
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                                        "text": "substance use",
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                                "text": " to",
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                    {
                        "url": "https://ourworldindata.org/cancer",
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                                "text": " ",
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                                "children": [
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                                        "text": "cancer rates",
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                                "text": "; there are important differences in health outcomes between the sexes. In a related post, my colleague Esteban Ortiz-Ospina looks at the evidence to answer the question \"",
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                        "url": "https://ourworldindata.org/why-do-women-live-longer-than-men",
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                                "children": [
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                                        "text": "Why do women live longer than men?",
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                        "children": [
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                                "text": "Here we focus on the youngest, asking, why do young boys die more often than girls?",
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                "text": [
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                        "text": "Child and infant mortality is higher for boys in nearly all countries",
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                        "text": "Child mortality measures the share of newborns who die before reaching their 5th birthday.\u00a0In the chart below we see the comparison of child mortality by sex.",
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                        "text": "Here, the mortality rate for boys is shown on the y-axis, and the mortality rate for girls on the x-axis. The grey line running diagonally across the chart marks where the mortality rate for both sexes is equal. In countries which lie above the grey line, the rate for boys is higher than for girls.",
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                        "text": "What's striking is that with exception of two countries \u2013 India and Tonga \u2013 child mortality is more common for boys in all countries of the world. This is also ",
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                                "text": "true for infant mortality",
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                        "text": ", which is the share of newborns who die within their 1st year of life. We study why India and Tonga are outliers ",
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                        "url": "https://ourworldindata.org/gender-ratio#infanticide-and-excess-female-mortality",
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                        "text": "Over the past half-century in particular, child mortality has been falling rapidly across the world. This has been ",
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                                "text": "true for boys and girls",
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                        "text": " alike.",
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                        "text": "It has been known for a long time that the mortality of boys is higher. As early as 1786 the physician, Dr Joseph Clarke, read a paper to the Royal Society of London on his observations that ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "\"mortality of males exceeds that of females in almost all stages of life, and particularly the earliest stages\"",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ".{ref}Clarke, J., & Price, R. (1786). XVII. Observations on some causes of the excess of the mortality of males above that of females. By Joseph Clarke, MD Physician to the Lying-in Hospital at Dublin. Communicated by the Rev. Richard Price, DDFRS in a letter to Charles Blagden, MD Sec. R. S. Philosophical Transactions of the Royal Society of London, (76), 349-362.{/ref}",
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                ],
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                "url": "https://ourworldindata.org/grapher/child-mortality-by-sex",
                "type": "chart",
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                "text": [
                    {
                        "text": "What do infants die from?",
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                "value": [
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                        "text": "Why is it the case that boys die more often than girls? First of all, it's important to understand what young children die from.",
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                ],
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                "value": [
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                        "children": [
                            {
                                "text": "In this chart we see global mortality rates in infants across different causes in 2017. This data comes from the IHME's ",
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                            }
                        ],
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                        "children": [
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                                "children": [
                                    {
                                        "text": "Global Burden of Disease",
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                        ],
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                    },
                    {
                        "children": [
                            {
                                "text": " study, which provides estimates by sex \u2013 on the y-axis we have plotted mortality rates in boys, and on the x-axis for girls. Just like the charts above, causes which lie above the grey line are more common in boys.",
                                "spanType": "span-simple-text"
                            }
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                        "children": [
                            {
                                "text": "The chart shows that for all major causes of death, mortality is higher in boys. The sex differences in the causes of infant deaths were already documented almost a century ago: in an impressive paper published in 1929, Bawkin explores the mortality sex ratio of specific diseases from countries across the world.",
                                "spanType": "span-simple-text"
                            }
                        ],
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                    },
                    {
                        "text": "{ref}Bakwin, H. (1929).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://search.proquest.com/docview/1301822705?pq-origsite=gscholar",
                        "children": [
                            {
                                "text": " The sex factor in infant mortality",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
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                        "children": [
                            {
                                "text": "Human Biology",
                                "spanType": "span-simple-text"
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                    {
                        "text": ", 1(1), 90.{/ref}",
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                "type": "text",
                "value": [
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                        "children": [
                            {
                                "text": "There are some causes \u2013",
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                    {
                        "url": "https://owid.cloud/hiv-aids",
                        "children": [
                            {
                                "text": " ",
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                            {
                                "children": [
                                    {
                                        "text": "HIV/AIDS",
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                    {
                        "children": [
                            {
                                "text": ", nutritional deficiencies, whooping cough, among others \u2013 for which the mortality rates are higher in girls. But overall, infant boys are more likely to die in childhood than girls.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
                    },
                    {
                        "text": "{ref}Sawyer, C. C. (2012).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1001287",
                        "children": [
                            {
                                "text": " Child mortality estimation: estimating sex differences in childhood mortality since the 1970s",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
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                        "children": [
                            {
                                "text": "PLoS Medicine",
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                    {
                        "text": ", 9(8), e1001287.{/ref}{ref}Naeye, R. L., Burt, L. S., Wright, D. L., Blanc, W. A., & Tatter, D. (1971).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://pediatrics.aappublications.org/content/48/6/902.short",
                        "children": [
                            {
                                "text": " Neonatal mortality, the male disadvantage",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
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                        "children": [
                            {
                                "text": "Pediatrics",
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                    {
                        "text": ", 48(6), 902-906.{/ref}{ref}This is also the explanation",
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                    },
                    {
                        "url": "http://www.searo.who.int/entity/health_situation_trends/data/chi/sex-diff-imr/en/",
                        "children": [
                            {
                                "text": " reported by",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": " the World Health Organization: \"",
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                    },
                    {
                        "children": [
                            {
                                "text": "Newborn girls have a biological advantage in survival over newborn boys. They have lesser vulnerability to perinatal conditions (including birth trauma, intrauterine hypoxia and birth asphyxia, prematurity, respiratory distress syndrome and neonatal tetanus), congenital anomalies, and such infectious diseases as intestinal infections and lower respiratory infections.",
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                        "text": "\"{/ref}",
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                "value": [
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                        "children": [
                            {
                                "text": "Boys are more vulnerable in two key ways: they are at higher risk of birth complications, and infectious disease. We explore the possible reasons for this below.",
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                            }
                        ],
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                ],
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                "url": "https://ourworldindata.org/grapher/infant-death-rates-by-cause-by-sex",
                "type": "chart",
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                "text": [
                    {
                        "text": "Boys are at higher risk of birth complications",
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                            {
                                "text": "From comparison of mortality rates in infant boys and girls, it becomes clear that boys are at higher risk of complications in the first few days of life: preterm births, asphyxia, birth defects and heart anomalies. But why?",
                                "spanType": "span-simple-text"
                            },
                            {
                                "spanType": "span-newline"
                            },
                            {
                                "text": " ",
                                "spanType": "span-simple-text"
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                                "spanType": "span-newline"
                            },
                            {
                                "text": "First of all, ",
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                    {
                        "children": [
                            {
                                "text": "boys are more likely to be born prematurely",
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                            }
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                    },
                    {
                        "children": [
                            {
                                "text": ": the share of boys born before full-term pregnancy is higher than for girls.",
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                            }
                        ],
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                    },
                    {
                        "text": "{ref}Peelen, M. J., Kazemier, B. M., Ravelli, A. C., De Groot, C. J., Van Der Post, J. A., Mol, B. W., \u2026 & Kok, M. (2016).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://obgyn.onlinelibrary.wiley.com/doi/pdf/10.1111/aogs.12929",
                        "children": [
                            {
                                "text": " Impact of fetal gender on the risk of preterm birth, a national cohort study",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "Acta obstetricia et gynecologica Scandinavica",
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                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 95(9), 1034-1041.{/ref}\u00a0This occurs naturally, but is exacerbated by the rate of induced preterm births. Boys tend to have a higher birthweight than girls \u2013 which can increase the risk of waiting to term to deliver \u2013 meaning that more boys are induced before the end of the pregnancy term.{ref}Zeitlin, J., Saurel-Cubizolles, M. J., de Mouzon, J., Rivera, L., Ancel, P. Y., Blondel, B., & Kaminski, M. (2002).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://academic.oup.com/humrep/article/17/10/2762/607779",
                        "children": [
                            {
                                "text": " Fetal sex and preterm birth: are males at greater risk?",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "Human Reproduction",
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                    {
                        "text": ", 17(10), 2762-2768.{/ref}\u00a0The chart above shows that more boys die from preterm births. The fact that preterm births are more common for boys contributes to this.",
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                ],
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                "type": "text",
                "value": [
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                        "children": [
                            {
                                "text": "Although boys are, on average, heavier than girls at birth, ",
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                        ],
                        "spanType": "span-fallback"
                    },
                    {
                        "children": [
                            {
                                "text": "they are less physiologically mature at birth",
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                    {
                        "children": [
                            {
                                "text": ".",
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                        "children": [
                            {
                                "text": "This means they are at higher risk of having delayed physiological function (such as lung function) and adverse neurological outcomes.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
                    },
                    {
                        "text": "{ref}Peacock, J. L., Marston, L., Marlow, N., Calvert, S. A., & Greenough, A. (2012).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.nature.com/articles/pr201150",
                        "children": [
                            {
                                "text": " Neonatal and infant outcome in boys and girls born very prematurely",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "Pediatric Research",
                                "spanType": "span-simple-text"
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                    },
                    {
                        "text": ", 71(3), 305.{/ref}{ref}Hintz, S. R., Kendrick, D. E., Vohr, B. R., Poole, W. K., Higgins, R. D., & Nichd Neonatal Research Network. (2006).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://onlinelibrary.wiley.com/doi/abs/10.1080/08035250600599727",
                        "children": [
                            {
                                "text": " Gender differences in neurodevelopmental outcomes among extremely preterm, extremely\u2010low\u2010birthweight infants",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Acta Paediatrica",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 95(10), 1239-1248.{/ref}\u00a0For example, poorer lung function in newborn boys has been shown for both term and preterm infants.{ref}Jones, M., Castile, R., Davis, S., Kisling, J., Filbrun, D., Flucke, R., \u2026 & Tepper, R. S. (2000).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.atsjournals.org/doi/full/10.1164/ajrccm.161.2.9903026",
                        "children": [
                            {
                                "text": " Forced expiratory flows and volumes in infants: normative data and lung growth",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "American Journal of Respiratory and Critical Care Medicine",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 161(2), 353-359.{/ref}{ref}Hoo, A. F., Henschen, M., Dezateux, C., Costeloe, K., & Stocks, J. (1998).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.atsjournals.org/doi/full/10.1164/ajrccm.158.3.9711057",
                        "children": [
                            {
                                "text": " Respiratory function among preterm infants whose mothers smoked during pregnancy",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "American Journal of Respiratory and Critical Care Medicine",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 158(3), 700-705.{/ref}\u00a0Studies have suggested that even in the case of straightforward pregnancies, lung maturation in boys lags that of girls by approximately one week.{ref}Fleisher, B., Kulovich, M. V., Hallman, M. I. K. K. O., & Gluck, L. O. U. I. S. (1985).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://europepmc.org/abstract/med/4022494",
                        "children": [
                            {
                                "text": " Lung profile: sex differences in normal pregnancy",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "Obstetrics and Gynecology",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 66(3), 327-330.{/ref}\u00a0These differences in maturity at birth are not restricted to lung function.{ref}Peacock, J. L., Marston, L., Marlow, N., Calvert, S. A., & Greenough, A. (2012).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.nature.com/articles/pr201150",
                        "children": [
                            {
                                "text": " Neonatal and infant outcome in boys and girls born very prematurely",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "Pediatric Research",
                                "spanType": "span-simple-text"
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                        ],
                        "spanType": "span-italic"
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                    {
                        "text": ", 71(3), 305.{/ref}",
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                "value": [
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                        "children": [
                            {
                                "text": "The reason for this difference has been an important question for decades \u2013 the answer is still not clear. But there are some leading hypotheses: surfactant production for lung function has been observed earlier in female fetuses, leading to improved airway flow in the lungs; estrogen has been shown to affect lung development positively in females; males, on average, have a higher birthweight meaning they may trade-off increased size for functional development; and the uterus may be less hospitable to male fetuses \u2013 the introduction of a Y chromosome in females can create an immunoreactive response to the central nervous system.",
                                "spanType": "span-simple-text"
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                        ],
                        "spanType": "span-fallback"
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                    {
                        "text": "{ref}DiPietro, J. A., & Voegtline, K. M. (2017).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.sciencedirect.com/science/article/pii/S0306452215006958",
                        "children": [
                            {
                                "text": " The gestational foundation of sex differences in development and vulnerability",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
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                    {
                        "text": ". ",
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                        "children": [
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                                "text": "Neuroscience",
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                    {
                        "text": ", 342, 4-20.{/ref}{ref}Townsel, C. D., Emmer, S. F., Campbell, W. A., & Hussain, N. (2017).",
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                    },
                    {
                        "url": "https://www.frontiersin.org/articles/10.3389/fped.2017.00006/full",
                        "children": [
                            {
                                "text": " Gender differences in respiratory morbidity and mortality of preterm neonates",
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                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
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                    {
                        "children": [
                            {
                                "text": "Frontiers in Pediatrics",
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                    {
                        "text": ", 5, 6.{/ref}",
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                        "children": [
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                                "text": "This, combined with a higher risk of premature birth may explain why boys have higher rates of asphyxia, respiratory infections and birth defects.",
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                "text": [
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                        "text": "Boys are at higher risk of infectious diseases",
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                        "children": [
                            {
                                "text": "Boys are also at higher risk of infectious diseases such as syphilis,",
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                    {
                        "url": "https://owid.cloud/malaria",
                        "children": [
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                                "children": [
                                    {
                                        "text": "malaria",
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                        "children": [
                            {
                                "text": ", respiratory infections, tetanus and diarrheal diseases. This is more generally true for a broad range of infections, spanning person-to-person, vector-borne, blood-borne, and food and water borne diseases.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
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                    {
                        "text": "{ref}Giefing\u2010Kr\u00f6ll, C., Berger, P., Lepperdinger, G., & Grubeck\u2010Loebenstein, B. (2015).",
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                    },
                    {
                        "url": "https://onlinelibrary.wiley.com/doi/full/10.1111/acel.12326",
                        "children": [
                            {
                                "text": " How sex and age affect immune responses, susceptibility to infections, and response to vaccination",
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                            }
                        ],
                        "spanType": "span-link"
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                    {
                        "text": ". ",
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                    {
                        "children": [
                            {
                                "text": "Aging Cell",
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                    {
                        "text": ", 14(3), 309-321.{/ref}",
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                        "children": [
                            {
                                "text": "We see this clearly when we compare mortality rates for boys and girls in the earlier chart. But why are boys more susceptible to infection?",
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                        "children": [
                            {
                                "text": "Overall, boys have weaker immune systems. There are two key hypotheses for why.",
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                "value": [
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                        "children": [
                            {
                                "children": [
                                    {
                                        "text": "The Y-chromosome in boys increases their vulnerability.",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-bold"
                            },
                            {
                                "text": " Biologically, males and females are differentiated by chromosomes: females have two X chromosomes (XX) and males one X and one Y chromosome (XY). Having two X chromosomes means that the newborn has a stronger immune system because X chromosomes contain a larger number of immune-related genes.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
                    },
                    {
                        "text": "{ref}Markle, J. G., & Fish, E. N. (2014).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.sciencedirect.com/science/article/pii/S1471490613001592",
                        "children": [
                            {
                                "text": " SeXX matters in immunity",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Trends in Immunology",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 35(3), 97-104.{/ref}{ref}Libert, C., Dejager, L., & Pinheiro, I. (2010).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.nature.com/articles/nri2815",
                        "children": [
                            {
                                "text": " The X chromosome in immune functions: when a chromosome makes the difference",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "Nature Reviews Immunology",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 10(8), 594.{/ref}\u00a0This means that, since females have two X chromosomes, they have a stronger immune response; boys on the other hand, are more vulnerable to X-linked infections.{ref}Waldron, I. (1983). Sex differences in human mortality: the role of genetic factors.",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.sciencedirect.com/science/article/pii/0277953683902344",
                        "children": [
                            {
                                "text": " ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "children": [
                                    {
                                        "text": "Social Science & Medicine",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-italic"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ", 17(6), 321-333.{/ref}",
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                "value": [
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                        "children": [
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                                "text": "This makes males more vulnerable to many infectious diseases. They are also more susceptible to specific genetic diseases where the defective genes are carried on either the X or Y chromosomes; this is because boys have only one X chromosome so a single recessive gene on that X chromosome results in the disease.",
                                "spanType": "span-simple-text"
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                                "text": "But the stronger immune response of females comes with a cost. It\u2019s the reason why women are more susceptible to autoimmune disorders such as HIV/AIDS.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
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                    {
                        "text": "{ref}Libert, C., Dejager, L., & Pinheiro, I. (2010).",
                        "spanType": "span-simple-text"
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                    {
                        "url": "https://www.nature.com/articles/nri2815",
                        "children": [
                            {
                                "text": " The X chromosome in immune functions: when a chromosome makes the difference",
                                "spanType": "span-simple-text"
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                        "spanType": "span-link"
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                    {
                        "text": ". ",
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                        "children": [
                            {
                                "text": "Nature Reviews Immunology",
                                "spanType": "span-simple-text"
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                    {
                        "text": ", 10(8), 594.{/ref}",
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                        "children": [
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                                "text": "Sex hormones may be another key reason for weaker immune systems in males. ",
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                        "spanType": "span-bold"
                    },
                    {
                        "children": [
                            {
                                "text": "Males have much higher amounts of testosterone which seem to inhibit two major parts of the immune system \u2013 B and T-lymphocytes.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
                    },
                    {
                        "text": "{ref}Fischer, J., Jung, N., Robinson, N., & Lehmann, C. (2015).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://link.springer.com/article/10.1007/s15010-015-0791-9",
                        "children": [
                            {
                                "text": " Sex differences in immune responses to infectious diseases",
                                "spanType": "span-simple-text"
                            }
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                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "Infection",
                                "spanType": "span-simple-text"
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                        "spanType": "span-italic"
                    },
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                        "text": ", 43(4), 399-403.{/ref}",
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                                "text": "Estrogen, on the other hand, acts as an effective regulator of this. Overall, male hormones weaken the immune system relative to females.",
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                        "children": [
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                                "text": "The male disadvantage",
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                                "text": "The fact that boys are more susceptible than girls to a range of health conditions is often summarized as the \u201cmale disadvantage\u201d. This is not restricted to childhood: the female advantage carries into adulthood. It\u2019s part of the reason ",
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                        "url": "https://ourworldindata.org/why-do-women-live-longer-than-men",
                        "children": [
                            {
                                "children": [
                                    {
                                        "text": "why women tend to live longer than men",
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                        "children": [
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                                "text": ". ",
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                                "text": "The leading explanations for the \"male disadvantage\" lie in the biological differences between the sexes. More specifically, differences in maturity, sex chromosomes, and hormones.",
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                                "text": "In circumstances where both sexes are treated equally, we would therefore expect infant and child mortality rates to be slightly higher for boys.",
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                "text": [
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                        "text": "Sex ratio through adulthood",
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                        "text": "The sex ratio \u2013 the number of males relative to females \u2013 at birth and in childhood are male-biased in almost every country.",
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                        "text": "\nIn previous discussion we covered why we'd expected this to be the case biologically.",
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                        "text": "How does the sex ratio change throughout adulthood?",
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                        "text": "In this chart we see the sex ratio \u2013 measured as the number of males per 100 females \u2013 at different ages through adolescence and adulthood.",
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                        "text": "In the global average for adolescents and young adults we see the result of both the male-bias in birth ratios and the large impact of populous countries such as China and India with very skewed sex ratios: At age 15 and 20, males outnumber females by 106 to 100.",
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                        "text": "But as we move through adulthood we see that this ratio is lower and lower. For 50-year-olds the ratio is close to 1-to-1; for 70-year-olds there are only 86 males per 100 females; and in the very oldest age bracket (people aged 100 and older) there are only 24 men per 100 women.",
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                        "text": "You can explore this data for any country of region of the world using the \"change country\" button in the top-left of the chart. You will see that for some countries this decline in the sex ratio with age is even more extreme: in Russia, for example, by age 50 there are only 91 males per 100 females; by 70 years old there are almost twice as many women as men.",
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                        "text": "In every country in the world ",
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                        "url": "https://ourworldindata.org/grapher/life-expectancy-of-women-vs-life-expectancy-of-women",
                        "children": [
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                                "text": "women tend to live longer than men",
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                    {
                        "text": ". Whilst this is true today, it hasn't always been the case. In his text '",
                        "spanType": "span-simple-text"
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                    {
                        "url": "https://ourworldindata.org/why-do-women-live-longer-than-men",
                        "children": [
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                                "text": "Why do women live longer than men?",
                                "spanType": "span-simple-text"
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                        "text": "' my colleague Esteban takes a look at the evidence and explanations for why this is the case.",
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                        "text": "Why do women live longer than men?",
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                        "text": "On average, women live longer than men \u2013 this is true for every country in the world. This fact plays an important role in how the sex ratio changes with age through adulthood.",
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                        "text": "A detailed discussion of why this is the case is available in our explainer on '",
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                        "text": "'.",
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                "text": [
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                        "text": "Missing girls and women",
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                "text": [
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                        "text": "Biology or discrimination: which countries have skewed sex ratios at birth?",
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                        "text": "Today, and at several points historically, the sex ratio at birth in some countries is too skewed to be explained by biological differences alone. The ",
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                    {
                        "url": "https://ourworldindata.org/gender-ratio#definitions",
                        "children": [
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                                "text": "'expected' sex ratio at birth",
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                        "text": " is around 105 males per 100 females.",
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                        "text": "In a recent study Chao et. al (2019) re-modelled sex ratios at birth (SRB) across the world based on a range of population sources, including census and household survey data.{ref}Chao, F., Gerland, P., Cook, A.R., Alkema, L. (2019). ",
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                    {
                        "url": "https://www.pnas.org/content/early/2019/04/09/1812593116",
                        "children": [
                            {
                                "text": "Systematic assessment of the sex ratio at birth for all countries and estimation of national imbalances and regional reference levels",
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                        "spanType": "span-link"
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                        "text": ". ",
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                        "children": [
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                                "text": "PNAS",
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                        "text": ".{/ref} The results are shown in the chart below since 1950. The authors identified 12 countries with strong statistical evidence of a skewed sex ratio: Albania, Armenia, Azerbaijan, China, Georgia, Hong Kong, India, Montenegro, South Korea, Taiwan, Tunisia, and Vietnam.{ref}Note that this does not imply that other countries do not have male preference or some evidence of a skewed sex ratio. Results of the Chao et al. (2019) study highlight those with the strongest statistical evidence of this imbalance.{/ref}",
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                        "text": "Most of these countries are in Asia. Why is this the case? Is there a biological or environmental difference, or is it the result of discrimination?",
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                        "children": [
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                                "text": "Hepatitis B was proposed then later debunked",
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                        "text": "Amartya Sen was the first scholars to publicly bring attention to the concept of \"missing women\" as a result of sex selective abortion, unequal treatment and infanticide of girls.{ref}Sen, Amartya (20 December 1990). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://web.archive.org/web/20130504072819/http://ucatlas.ucsc.edu/gender/Sen100M.html",
                        "children": [
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                                "text": "More Than 100 Million Women Are Missing",
                                "spanType": "span-simple-text"
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                        "spanType": "span-link"
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                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "New York Review of Books",
                                "spanType": "span-simple-text"
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                        "spanType": "span-italic"
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                    {
                        "text": ". 37 (20).{/ref}",
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                        "text": "The reason for this skew in sex ratio has been previously challenged. One of the leading hypotheses was put forward by economist Emily Oster. In a 2005 paper she argued that a large proportion \u2013 approximately 45%, around 75% in China, 20-50% in Egypt and western Asia, and under 20% in India, Bangladesh, Pakistan, and Nepal \u2013 of the overrepresentation of men could be explained by the high rates of hepatitis B carriers in Asia.{ref}Oster, E. (2005). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.journals.uchicago.edu/doi/abs/10.1086/498588",
                        "children": [
                            {
                                "text": "Hepatitis B and the Case of the Missing Women",
                                "spanType": "span-simple-text"
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                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "Journal of Political Economy",
                                "spanType": "span-simple-text"
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                        ],
                        "spanType": "span-italic"
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                        "text": ", 113(6), 1163-1216.{/ref} The rationale was that (1) hepatitis B carriers have an offspring sex ratio much more in favour of boys (1.5 boys per girl), and (2) that hepatitis B carrier rates were notably higher in Asian cultures than in the West. The combination of these two observations Oster calculated could account for a large proportion of the \"missing women\".",
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                        "text": "A few years later, Oster debunked her own hypothesis on the role of hepatitis B in a paper titled \"Hepatitis B does not explain male-biased sex ratios in China\". In a study of 67,000 people in China \u2013 15% of which were hepatitis B carriers \u2013 Oster and colleagues found no link between hepatitis B status and offspring sex ratio.{ref}Oster, E., Chen, G., Yu, X., & Lin, W. (2010). ",
                        "spanType": "span-simple-text"
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                    {
                        "url": "https://www.nber.org/papers/w13971",
                        "children": [
                            {
                                "text": "Hepatitis B does not explain male-biased sex ratios in China",
                                "spanType": "span-simple-text"
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                        "spanType": "span-link"
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                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "Economics Letters",
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                        "text": ", 107(2), 142-144.{/ref} The hepatitis carrier status of neither the mother or the father had an effect on the offspring sex: carriers were not more likely to have a boy than non-carriers. The authors concluded that hepatitis B rates could not explain the skewed sex ratio in China.",
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                        "text": "Other studies \u2013 such as that by Lin and Luoh (2008) in Taiwan \u2013 have also found minimal to no effect of hepatitis B on the sex ratio.{ref}Lin, M. J., & Luoh, M. C. (2008). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.jstor.org/stable/29730171",
                        "children": [
                            {
                                "text": "Can hepatitis B mothers account for the number of missing women? Evidence from three million newborns in Taiwan",
                                "spanType": "span-simple-text"
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                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "American Economic Review",
                                "spanType": "span-simple-text"
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                        "spanType": "span-italic"
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                    {
                        "text": ", 98(5), 2259-73.{/ref}{ref}Monica Das Gupta, ",
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                    },
                    {
                        "url": "https://academic.oup.com/wbro/article-abstract/23/2/201/1662748",
                        "children": [
                            {
                                "text": "Can Biological Factors Like Hepatitis B Explain the Bulk of Gender Imbalance in China? A Review of the Evidence",
                                "spanType": "span-simple-text"
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                        ],
                        "spanType": "span-link"
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                    {
                        "text": ", ",
                        "spanType": "span-simple-text"
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                        "children": [
                            {
                                "text": "The World Bank Research Observer",
                                "spanType": "span-simple-text"
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                    {
                        "text": ", Volume 23, Issue 2, Fall 2008, Pages 201\u2013217.{/ref}",
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                        "children": [
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                                "text": "Sex-selective abortions and discrimination against girls",
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                        "text": "After the hepatitis B hypothesis was debunked, no clear evidence of a biological factor in such skewed sex ratios has emerged. There is some variability in the ",
                        "spanType": "span-simple-text"
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                    {
                        "url": "https://ourworldindata.org/gender-ratio#definitions",
                        "children": [
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                                "text": "\"expected\" sex ratio",
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                    },
                    {
                        "text": " which may result from biological or environmental factors \u2013 a figure of 105 boys per 100 girls is usually adopted, but often this can vary from 103 to 107 boys per 100 girls. But the natural variability of the sex ratio is too small to explain the high ratios in some countries.",
                        "spanType": "span-simple-text"
                    }
                ],
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                "type": "text",
                "value": [
                    {
                        "text": "The evidence for sex-selective abortion and discrimination against girls is now strong across several countries. Not only does the increase in sex ratios coincide with the availability of prenatal sex determination technologies, there is also clear evidence from studies investigating the use and promotion of such methods.",
                        "spanType": "span-simple-text"
                    }
                ],
                "parseErrors": []
            },
            {
                "type": "text",
                "value": [
                    {
                        "text": "In India, for example, prenatal diagnosis (PD) became available in the 1970s, shortly after legalization of medical abortion in 1971.{ref}Madan, K., & Breuning, M. H. (2014). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4052431/",
                        "children": [
                            {
                                "text": "Impact of prenatal technologies on the sex ratio in India: an overview",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Genetics in Medicine",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 16(6), 425.{/ref} Whilst its use was intended for detection of abnormalities, it was soon used and promoted by the Indian medical profession for sex determination.{ref}Sharma, B. R., Gupta, N., & Relhan, N. (2007). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.sciencedirect.com/science/article/pii/S0033350607000960",
                        "children": [
                            {
                                "text": "Misuse of prenatal diagnostic technology for sex-selected abortions and its consequences in India",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "Public Health",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 121(11), 854-860.{/ref} Even after its use for sex determination was prohibited, studies suggest many gynecologists did not consider sex-selection abortion to be unethical and argued that it was an important intervention to balance population control with the desire for sons.{ref}Correspondent, L. I. (1983). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.ncbi.nlm.nih.gov/pubmed/11644254",
                        "children": [
                            {
                                "text": "Misuse of amniocentesis",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Lancet",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 321, 812-813.{/ref}",
                        "spanType": "span-simple-text"
                    }
                ],
                "parseErrors": []
            },
            {
                "type": "text",
                "value": [
                    {
                        "text": "Results from some of the earliest studies on abortions following the availability of prenatal sex determination are striking. Over the year from 1976 to 1977, at an urban hospital in India, 96% of the girls who were tested were aborted; in contrast, all of the 250 boys tested \u2013 including those with an identified risk of genetic defect \u2013 were born.{ref}Ramanamma, A., & Bambawale, U. (1980). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.sciencedirect.com/science/article/pii/0160798780900599",
                        "children": [
                            {
                                "text": "The mania for sons: an analysis of social values in South Asia",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Social Science & Medicine. Part B: Medical Anthropology",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 14(2), 107-110.{/ref} At a clinic in Mumbai, all of the 15,914 abortions after sex determination in 1984/85 were girls. Results from another six hospitals in the city found 7,999 of the 8,000 aborted fetuses in 1988 were girls.{ref}Tandon SL, Sharma R. (2006). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "http://www.sascv.org/ijcjs/previousissues.html",
                        "children": [
                            {
                                "text": "Female foeticide and infanticide in India: an analysis of crimes against girl children",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "International Journal of Criminal Justice Science",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ".{/ref}",
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                "type": "text",
                "value": [
                    {
                        "text": "The evidence that highly skewed sex ratios at birth have been largely the result of gender discrimination and selective abortions has been well-established across several countries. We discuss the reasons for this discrimination ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/gender-ratio#why-is-there-preference-for-a-son",
                        "children": [
                            {
                                "children": [
                                    {
                                        "text": "here",
                                        "spanType": "span-simple-text"
                                    }
                                ],
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                        "text": ".",
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                "type": "text",
                "value": [
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                        "text": "There are some additional hypotheses as to why the sex ratio at birth is skewed in some countries. Based on Chinese census data, Shi and Kennedy (2016) argue that the skew in China's sex ratio is not the result of selective abortion practices, but much more the result of administrative anomalies.{ref}Shi, Y., & Kennedy, J. J. (2016). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.cambridge.org/core/journals/china-quarterly/article/delayed-registration-and-identifying-the-missing-girls-in-china/0759987A48A37E3D2CFE157778747E33",
                        "children": [
                            {
                                "text": "Delayed registration and identifying the \u201cmissing girls\u201d in China",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ".\u00a0",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "The China Quarterly",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ",\u00a0",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "228",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 1018-1038.{/ref} The authors argue that the one-child policy led some parents to postpone the registration of daughters (making them appear \"missing\"), but that they appear later in Chinese census data. A year later, Cai (2017) challenged the authors' conclusions in support of the conventional hypothesis that this is not a statistical artefact, but a real demographic\u00a0 and social challenge.{ref}Cai, Y. (2017). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.cambridge.org/core/journals/china-quarterly/article/missing-girls-or-hidden-girls-a-comment-on-shi-and-kennedys-delayed-registration-and-identifying-the-missing-girls-in-china/61E21855F8A1D958660973841BBC46FD",
                        "children": [
                            {
                                "text": "Missing Girls or Hidden Girls? A Comment on Shi and Kennedy's \u201cDelayed Registration and Identifying the \u2018Missing Girls\u2019 in China\u201d",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ".\u00a0",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "The China Quarterly",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ",\u00a0",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "231",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 797-803.{/ref}",
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                ],
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            {
                "text": [
                    {
                        "text": "Infanticide",
                        "spanType": "span-simple-text"
                    }
                ],
                "type": "heading",
                "level": 2,
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                "value": [
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                        "text": "Sex discrimination can occur prenatally (in the form of sex-selective abortions, as we discuss ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/gender-ratio#biology-or-discrimination-which-countries-have-skewed-sex-ratios-at-birth",
                        "children": [
                            {
                                "children": [
                                    {
                                        "text": "here",
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                        ],
                        "spanType": "span-link"
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                    {
                        "text": ") or postnatally when it can lead to the death of a child in the very worst cases. The death of a child due to sex discrimination can be brought about in a deliberate killing of an infant (infanticide) or can be caused by neglect or poor and unequal treatment.",
                        "spanType": "span-simple-text"
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                "type": "text",
                "value": [
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                        "text": "Over time, prenatal discrimination has increased as both abortions and sex determination technologies have become more readily available. Nonetheless, postnatal discrimination still occurs and has a long history.",
                        "spanType": "span-simple-text"
                    }
                ],
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            {
                "text": [
                    {
                        "children": [
                            {
                                "text": "Infanticide has a long history",
                                "spanType": "span-simple-text"
                            }
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                "type": "heading",
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                "value": [
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                        "text": "Infanticide (or infant homicide) \u2013 the deliberate killing of newborns and infants \u2013 has a long history.{ref}Moseley, K. L. (1985).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://heinonline.org/HOL/LandingPage?handle=hein.journals/ilmed1&div=42&id=&page=",
                        "children": [
                            {
                                "text": " The history of infanticide in Western society",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Issues in Law & Medicine",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 1, 345.{/ref}{ref}Levittan, M. (2012). The history of infanticide: exposure, sacrifice, and femicide. ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Violence and Abuse in Society. Understanding a Global Crisis",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ". Santa Barbara, ABC-CLIO, 83-130.{/ref}\u00a0From hunter-gatherers to ancient civilizations to the present day: infanticide has spanned all periods of history. In fact, anthropologist Laila Williamson goes as far to say: \u201cInfanticide has been practiced on every continent and by people on every level of cultural complexity, from hunter gatherers to high civilizations, including our own ancestors. Rather than being an exception, then, it has been the rule.\"{ref}Williamson, Laila (1978). \"Infanticide: an anthropological analysis\". In Kohl, Marvin (ed.). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Infanticide and the Value of Life",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ". NY: ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://en.wikipedia.org/wiki/Prometheus_Books",
                        "children": [
                            {
                                "text": "Prometheus Books",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". pp. 61\u201375.{/ref}",
                        "spanType": "span-simple-text"
                    }
                ],
                "parseErrors": []
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                "type": "text",
                "value": [
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                        "children": [
                            {
                                "text": "And humans are not alone. From birds to rodents; fish to mammals; we find evidence of infanticide across the animal kingdom.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
                    },
                    {
                        "text": "{ref}Hausfater, G., & Hrdy, S. B. (2017). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Infanticide: comparative and evolutionary perspectives",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ". Routledge.{/ref}",
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                ],
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                "type": "text",
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                        "children": [
                            {
                                "text": "There are some common misconceptions today surrounding the practice of infanticide. Although the term is now often adopted as a synonym for \u2018female infanticide\u2019 \u2013 the killing of unwanted girls \u2013 the gender specifics and drivers of infanticide depend on context and time in history.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
                    },
                    {
                        "text": "{ref}Scott, E. (2017, June). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://books.google.co.uk/books?hl=en&lr=&id=n98jDwAAQBAJ&oi=fnd&pg=PA143&dq=unpicking+a+myth:+the+infanticide&ots=2XS6lFMoJO&sig=AdzrpXxZR3RWGNd-qf0FducA81I#v=onepage&q=unpicking%20a%20myth%3A%20the%20infanticide&f=false",
                        "children": [
                            {
                                "text": "Unpicking a myth: the infanticide of female and disabled infants in antiquity",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". In ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "TRAC 2000: Proceedings of the Tenth Annual Theoretical Archaeology Conference. London 2000",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": " (p. 143). Oxbow Books.{/ref}",
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                "text": [
                    {
                        "children": [
                            {
                                "text": "Historical evidence and estimates of infanticide",
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                                    {
                                        "text": "A number of researchers have studied the demographic, health and cultural profiles of prehistoric societies. In rare cases they can use indirect evidence of the fossil record; but many rely on modern hunter-gatherer societies today.{ref}This of course introduces uncertainty as to how good an analogue modern hunter-gatherers are to prehistoric societies. Modern hunter-gatherer societies may have some contact and transfer with external influence. As a result, researchers often focus on societies with as little external influence as possible, for example having no nutritional, health, sanitation or technology transfer.{/ref}",
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                                "text": "Estimates for infanticide in prehistoric societies are very high. Using recent hunter-gatherer societies as a proxy, some studies suggest anywhere from 15% to 50% of newborns were killed in the first year of life.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
                    },
                    {
                        "text": "{ref}Birdsell, Joseph, B. (1986). \"Some predictions for the Pleistocene based on equilibrium systems among recent hunter gatherers\". In Lee, Richard & Irven DeVore (ed.). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Man the Hunter",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ". Aldine Publishing Co. p. 239.{/ref}\u00a0Other estimates are lower, but still very high: in the range of 15-20%.{ref}Williamson, Laila (1978). \"Infanticide: an anthropological analysis\". In Kohl, Marvin (ed.). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Infanticide and the Value of Life",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ". NY: ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://en.wikipedia.org/wiki/Prometheus_Books",
                        "children": [
                            {
                                "text": "Prometheus Books",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". pp. 61\u201375.{/ref}",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": " ",
                                "spanType": "span-simple-text"
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                        "children": [
                            {
                                "text": "Hill & Walker (2007) looked at the demographic profiles, death rates and causes of death of recent hunter-gatherers: the Hiwi group of Venezuela. They did this using census and interviews gathered over a seven year period.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
                    },
                    {
                        "text": "{ref}Hill, K., Hurtado, A. M., & Walker, R. S. (2007). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.sciencedirect.com/science/article/pii/S0047248406002193",
                        "children": [
                            {
                                "text": "High adult mortality among Hiwi hunter-gatherers: Implications for human evolution",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Journal of Human Evolution",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "52",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": "(4), 443-454.{/ref}\u00a0They found very high rates of infant death from violence. Infant mortality rates in the past were very high \u2013 most studies suggest around a quarter of newborns did not survive the first year of life.\u00a0",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "In the Hiwi hunter-gatherers, researchers found homicide to be the second largest cause of death, accounting for 30%. They also found large sex differences: infanticide rates were four times higher for girls than boys.",
                                "spanType": "span-simple-text"
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                "value": [
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                        "children": [
                            {
                                "text": "Other studies of modern hunter-gatherer societies analysed the sex ratio of infants to estimate the prevalence of infanticide. Very skewed sex ratio of infants is suggestive of select infanticide. In studying 86 hunter-gatherer bands across North America, South America, Africa, Asia and Australia, researchers found high levels of female infanticide across 77 of them.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
                    },
                    {
                        "text": "{ref}Divale, W. T. (1972). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.tandfonline.com/doi/abs/10.1080/00438243.1972.9979534",
                        "children": [
                            {
                                "text": "Systemic population control in the middle and upper palaeolithic: Inferences based on contemporary hunter\u2010gatherers",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "World Archaeology",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", ",
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                        "children": [
                            {
                                "text": "4",
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                    {
                        "text": "(2), 222-243.{/ref}",
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                        "children": [
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                                "text": "This is shown in the table, where there were many more young males than females in bands where infanticide was reported as \u2018common\u2019 or \u2018occasional\u2019.",
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                "value": "<div class=\"raw-html-table__container\"><table><thead><tr><th scope=\"col\" colspan=\"1\">Infanticide reported as:</th><th scope=\"col\" colspan=\"1\">Youth sex ratio <br>(males per 100 females)</th><th scope=\"col\" colspan=\"1\">Adult sex ratio <br>(males per 100 females)</th><th scope=\"col\" colspan=\"1\">Number of hunter-gathering bands</th></tr></thead><tbody><tr><td colspan=\"1\" rowspan=\"1\">Common</td><td colspan=\"1\" rowspan=\"1\">138</td><td colspan=\"1\" rowspan=\"1\">105</td><td colspan=\"1\" rowspan=\"1\">71</td></tr><tr><td colspan=\"1\" rowspan=\"1\">Occasional</td><td colspan=\"1\" rowspan=\"1\">138</td><td colspan=\"1\" rowspan=\"1\">80</td><td colspan=\"1\" rowspan=\"1\">6</td></tr><tr><td colspan=\"1\" rowspan=\"1\">Not common</td><td colspan=\"1\" rowspan=\"1\">100</td><td colspan=\"1\" rowspan=\"1\">85</td><td colspan=\"1\" rowspan=\"1\">3</td></tr><tr><td colspan=\"1\" rowspan=\"1\">Not practised</td><td colspan=\"1\" rowspan=\"1\">94</td><td colspan=\"1\" rowspan=\"1\">83</td><td colspan=\"1\" rowspan=\"1\">6</td></tr></tbody></table></div>",
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                                "text": "The practice of infanticide was not just common in prehistoric societies, but was also very common in many \u2013 but not all \u2013 ancient cultures.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
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                    {
                        "text": "{ref}Langer, W. L. (1974). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://search.proquest.com/docview/1305583868",
                        "children": [
                            {
                                "text": "Infanticide: A historical survey",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "The Journal of Psychohistory",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", ",
                        "spanType": "span-simple-text"
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                        "children": [
                            {
                                "text": "1",
                                "spanType": "span-simple-text"
                            }
                        ],
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                    {
                        "text": "(3), 353.{/ref}\u00a0Evidence for this exists either in the form of preserved burial remains, documented records or writings suggestive of the practice.{ref}Milner, Larry S. (2000). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Hardness of Heart / Hardness of Life: The Stain of Human Infanticide",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ". Lanham/New York/Oxford: University Press of America.{/ref}",
                        "spanType": "span-simple-text"
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                ],
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                "text": [
                    {
                        "children": [
                            {
                                "text": "Both sexes",
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                            }
                        ],
                        "spanType": "span-bold"
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                    {
                        "text": " are victims of infanticide",
                        "spanType": "span-simple-text"
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                "level": 3,
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                                "text": "It\u2019s a common assumption that infanticide relates only to female infanticide: the killing of unwanted girls.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
                    },
                    {
                        "text": "{ref}Scott, E. (2017, June). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://books.google.co.uk/books?hl=en&lr=&id=n98jDwAAQBAJ&oi=fnd&pg=PA143&dq=unpicking+a+myth:+the+infanticide&ots=2XS6lFMoJO&sig=AdzrpXxZR3RWGNd-qf0FducA81I#v=onepage&q=unpicking%20a%20myth%3A%20the%20infanticide&f=false",
                        "children": [
                            {
                                "text": "Unpicking a myth: the infanticide of female and disabled infants in antiquity",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". In ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "TRAC 2000: Proceedings of the Tenth Annual Theoretical Archaeology Conference. London 2000",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": " (p. 143). Oxbow Books.{/ref}\u00a0But the role or direction of gender discrimination \u2013 either towards boys or girls \u2013 is context-dependent.{ref}Hughes, A. L. (1981). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.sciencedirect.com/science/article/pii/0162309581900236",
                        "children": [
                            {
                                "text": "Female infanticide: Sex ratio manipulation in humans",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Ethology and Sociobiology",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 2(3), 109-111.{/ref}",
                        "spanType": "span-simple-text"
                    }
                ],
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            {
                "type": "text",
                "value": [
                    {
                        "children": [
                            {
                                "text": "Sometimes here is no clear gender discrimination, and it occurs for both sexes.",
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                            }
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                        "spanType": "span-fallback"
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                ],
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                "type": "text",
                "value": [
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                        "children": [
                            {
                                "text": "There is of course significant evidence of female-selective infanticide throughout history: we see that in the sex ratio of many hunter-gatherer societies above through to skewed ratios in Medieval England.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
                    },
                    {
                        "text": "{ref}Kellum, B. A. (1974). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://search.proquest.com/openview/c1ae81634e9d46b2e7402da67bc5eeef/1?pq-origsite=gscholar&cbl=1816657",
                        "children": [
                            {
                                "text": "Infanticide in England in the later Middle Ages",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "The Journal of Psychohistory",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", ",
                        "spanType": "span-simple-text"
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                        "children": [
                            {
                                "text": "1",
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                        ],
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                    {
                        "text": "(3), 367.{/ref}\u00a0Evidence of male-selective infanticide is rarer, but does exist: in a sample of 93 preindustrial culture, 9 showed evidence of female-selective, while 1 showed male-selective infanticide.{ref}Hughes, A. L. (1981). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.sciencedirect.com/science/article/pii/0162309581900236",
                        "children": [
                            {
                                "text": "Female infanticide: Sex ratio manipulation in humans",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Ethology and Sociobiology",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 2(3), 109-111.{/ref}",
                        "spanType": "span-simple-text"
                    }
                ],
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                "type": "text",
                "value": [
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                        "children": [
                            {
                                "text": "Even today, cases on infanticide still exist, despite being outlawed in most countries.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-fallback"
                    },
                    {
                        "text": "{ref}Cecilia Lai\u2010wan, C., Eric, B., & Celia Hoi\u2010yan, C. (2006).",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=Cecilia+Lai%E2%80%90wan%2C+C.%2C+Eric%2C+B.%2C+%26+Celia+Hoi%E2%80%90yan%2C+C.+%282006%29.+Attitudes+to+and+practices+regarding+sex+selection+in+China.+Prenatal+Diagnosis%3A+Published+in+Affiliation+With+the+International+Society+for+Prenatal+Diagnosis%2C+26%287%29%2C+610-613.&btnG=",
                        "children": [
                            {
                                "text": " Attitudes to and practices regarding sex selection in China",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Prenatal Diagnosis: Published in Affiliation With the International Society for Prenatal Diagnosis",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 26(7), 610-613.{/ref} Infanticide occurs in Western countries: in some (such as the United States) boys make up a higher share of infant homicides.{ref}Porter, T., & Gavin, H. (2010). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://journals.sagepub.com/doi/abs/10.1177/1524838010371950",
                        "children": [
                            {
                                "text": "Infanticide and neonaticide: a review of 40 years of research literature on incidence and causes",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Trauma, Violence, & Abuse",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "11",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": "(3), 99-112.{/ref}\u00a0But the most widely prevalent \u2013 and selection that has a significant impact on gender ratio \u2013 is female infanticide. This remains reported across countries with a strong son preference: India and China are the most documented examples.{ref}Chunkath, S. R., & Athreya, V. B. (1997). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.jstor.org/stable/4405340",
                        "children": [
                            {
                                "text": "Female infanticide in Tamil Nadu: some evidence",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Economic and political weekly",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", WS21-WS28.{/ref}{ref}Lee, B. J. (1981). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.jstor.org/stable/41298766",
                        "children": [
                            {
                                "text": "Female infanticide in China",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Historical Reflections/R\u00e9flexions Historiques",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 163-177.{/ref}",
                        "spanType": "span-simple-text"
                    }
                ],
                "parseErrors": []
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            {
                "type": "text",
                "value": [
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                        "children": [
                            {
                                "text": "Infanticide is the most direct case of postnatal sex selection. More often overlooked is the excess mortality which results from neglect and unequal treatment of girls. This is \u2018excess female mortality\u2019 is sometimes often referred to as \u2018delayed infanticide\u2019.",
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                            }
                        ],
                        "spanType": "span-fallback"
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                "parseErrors": []
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            {
                "text": [
                    {
                        "text": "Excess female mortality",
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                ],
                "type": "heading",
                "level": 2,
                "parseErrors": []
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                        "children": [
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                                "text": "Poor treatment of girls results in increased mortality in childhood",
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                        "spanType": "span-bold"
                    },
                    {
                        "spanType": "span-newline"
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                    {
                        "text": "In almost every country young boys are more likely to die in childhood than girls \u2013 as we explore ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/gender-ratio#why-do-boys-die-more-often-than-girls",
                        "children": [
                            {
                                "children": [
                                    {
                                        "text": "here",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-bold"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ", there are several biological reasons for is. But this is not true in a few counties \u2013 India is one notable example today. There, girls die more often than boys.",
                        "spanType": "span-simple-text"
                    }
                ],
                "parseErrors": []
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            {
                "type": "text",
                "value": [
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                        "text": "When we compare infant (under one year old) and child (under-5s) mortality rates between boys and girls in India we see that the difference is bigger for the older age group. While infant mortality rates are approximately the same, the child mortality rate for girls is higher.",
                        "spanType": "span-simple-text"
                    }
                ],
                "parseErrors": []
            },
            {
                "type": "text",
                "value": [
                    {
                        "text": "Let's then focus on children rather than infants. In the chart here we see mortality rates for boys (on the y-axis) and girls (on the x-axis) for various causes in India. This data is shown for children aged 1-4 years old in 2017. Here we see that for many, death rates are significantly higher for girls. Some of these \u2013 hepatitis, measles or tuberculosis, for example \u2013 we expect to be higher for girls. But not for infections, respiratory and diarrheal diseases. Note also the much higher mortality rates for nutritional deficiencies and protein-energy malnutrition for girls.",
                        "spanType": "span-simple-text"
                    }
                ],
                "parseErrors": []
            },
            {
                "url": "https://ourworldindata.org/grapher/child-deaths-by-cause-by-sex-india",
                "type": "chart",
                "parseErrors": []
            },
            {
                "type": "text",
                "value": [
                    {
                        "text": "Poorer health outcomes for girls across some countries \u2013 often in Asia and not restricted to India \u2013 has been well-documented.{ref}Million Death Study Collaborators. (2010). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.sciencedirect.com/science/article/pii/S0140673610614614",
                        "children": [
                            {
                                "text": "Causes of neonatal and child mortality in India: a nationally representative mortality survey",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "The Lancet",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 376(9755), 1853-1860.{/ref}{ref}Raj, A., McDougal, L. P., & Silverman, J. G. (2015). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://link.springer.com/article/10.1007/s10995-014-1513-0",
                        "children": [
                            {
                                "text": "Gendered effects of siblings on child malnutrition in South Asia: cross-sectional analysis of demographic and health surveys from Bangladesh, India, and Nepal",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Maternal and Child Health Journal",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 19(1), 217-226.{/ref} Even for some countries where the child mortality rate remains higher in boys than for the girls, death rates for girls are still higher than would be expected.",
                        "spanType": "span-simple-text"
                    }
                ],
                "parseErrors": []
            },
            {
                "type": "text",
                "value": [
                    {
                        "text": "Social preference for a boy has resulted in unequal treatment of young girls in a number of ways. Studies have shown in some countries:",
                        "spanType": "span-simple-text"
                    }
                ],
                "parseErrors": []
            },
            {
                "type": "list",
                "items": [
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "poorer nutrition for girls and unequal food distribution;{ref}Aurino, E. (2017). ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://www.sciencedirect.com/science/article/pii/S1570677X16301666",
                                "children": [
                                    {
                                        "text": "Do boys eat better than girls in India? Longitudinal evidence on dietary diversity and food consumption disparities among children and adolescents",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "children": [
                                    {
                                        "text": "Economics & Human Biology",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-italic"
                            },
                            {
                                "text": ", 25, 99-111.{/ref}",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "less breastfeeding from mothers for daughters than for sons;{ref}Jayachandran, S., & Kuziemko, I. (2011). ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://academic.oup.com/qje/article-abstract/126/3/1485/1854553",
                                "children": [
                                    {
                                        "text": "Why do mothers breastfeed girls less than boys? Evidence and implications for child health in India",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "children": [
                                    {
                                        "text": "The Quarterly Journal of Economics",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-italic"
                            },
                            {
                                "text": ", 126(3), 1485-1538.{/ref}",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "lower healthcare utilization for girls;{ref}Ghosh, N., Chakrabarti, I., Chakraborty, M., & Biswas, R. (2013). ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://www.ijmedph.org/article/60?qt-sidebar_tabs=2",
                                "children": [
                                    {
                                        "text": "Factors affecting the healthcare-seeking behavior of mothers regarding their children in a rural community of Darjeeling district, West Bengal",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "children": [
                                    {
                                        "text": "International Journal of Medicine and Public Health",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-italic"
                            },
                            {
                                "text": ", 3(1).{/ref}{ref}Barcellos, S. H., Carvalho, L. S., & Lleras-Muney, A. (2014). ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://www.aeaweb.org/articles?id=10.1257/app.6.1.157",
                                "children": [
                                    {
                                        "text": "Child gender and parental investments in India: Are boys and girls treated differently?",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "children": [
                                    {
                                        "text": "American Economic Journal: Applied Economics",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-italic"
                            },
                            {
                                "text": ", 6(1), 157-89.{/ref}",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
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                        "type": "text",
                        "value": [
                            {
                                "text": "during pregnancy there is evidence of preferential treatment for boys with more antenatal visits and increased tetanus vaccinations.{ref}Bharadwaj, P., & Lakdawala, L. K. (2013). ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=Bharadwaj%2C+P.%2C+%26+Lakdawala%2C+L.+K.+%282013%29.+Discrimination+begins+in+the+womb%3A+Evidence+of+sex-selective+prenatal+investments.+Journal+of+Human+Resources%2C+48%281%29%2C+71-113.&btnG=",
                                "children": [
                                    {
                                        "text": "Discrimination begins in the womb: Evidence of sex-selective prenatal investments",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "children": [
                                    {
                                        "text": "Journal of Human Resources",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-italic"
                            },
                            {
                                "text": ", 48(1), 71-113.{/ref}",
                                "spanType": "span-simple-text"
                            }
                        ],
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                ],
                "parseErrors": []
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                "type": "text",
                "value": [
                    {
                        "text": "This combination of poorer nutrition and healthcare investment can result in higher mortality rates for girls, but also to excess mortality for women in later stages of life.",
                        "spanType": "span-simple-text"
                    }
                ],
                "parseErrors": []
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            {
                "text": [
                    {
                        "text": "How many women are missing?",
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                    }
                ],
                "type": "heading",
                "level": 2,
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                "value": [
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                        "text": "The term 'missing women' was first coined by Indian economist Amartya Sen in a 1990 article; he estimated \"more than 100 million women are missing\".{ref}Sen, A. (1990). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "http://www.ouazad.com/nyustats/resources/reading-week1.pdf",
                        "children": [
                            {
                                "text": "More than 100 million women are missing",
                                "spanType": "span-simple-text"
                            }
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                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
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                    {
                        "children": [
                            {
                                "text": "The New York Review of Books",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 37(20), 61-66.{/ref}",
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                        "text": "'Missing women' refers to the shortfall of women from the number we would expect in the absence of sex discrimination. It is the sum of women who are missing at birth (as a result of sex-selective prenatal practices such as abortion) and excess female mortality later in life (either through infanticide, child neglect or maltreatment).",
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                "value": [
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                        "text": "Many researchers have tried to calculate the number of missing women. Using sex ratios at birth, and at different ages we can compare the observed and expected values: the difference is then defined as girls and women who are missing.",
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                        "text": "There are very obvious challenges in calculating this figure. For the observed sex ratio, there is the concern of how accurate the reported number of births, males and females are. The other major issue is knowing exactly what the baseline/expected ratio of males to females would be at each stage in life. For example, the ",
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                    },
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                        "url": "https://ourworldindata.org/gender-ratio#definitions",
                        "children": [
                            {
                                "text": "'expected' sex ratio at birth",
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                            }
                        ],
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                    },
                    {
                        "text": " is quoted as 105 male births per 100 female births. But through time and across the world, this can often vary between 103 to 107 male births per 100 female births. The combination of these measurement issues means any estimate of the number of missing women will come with fairly high uncertainty.",
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                "value": [
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                        "text": "In the table here we provide a summary of a range of estimates \u2013 note here that the year of the estimate is different for each.",
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                        "children": [
                            {
                                "text": " ",
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                        "text": "Here we see that although there is significant uncertainty in these estimates, all are within the range of over 50 million by 1990, and likely upwards of 100 million today.",
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                        "text": "In the chart we see some of the most recent estimates of missing women from 1970 through to 2015 from Bongaarts & Guilmoto (2015).{ref}Bongaarts, J., & Guilmoto, C. Z. (2015). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=doi.org%2F10.1111%2Fj.1728-4457.2015.00046.x&btnG=",
                        "children": [
                            {
                                "text": "How many more missing women? Excess female mortality and prenatal sex selection, 1970\u20132050",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Population and Development Review",
                                "spanType": "span-simple-text"
                            }
                        ],
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                    },
                    {
                        "text": ", 41(2), 241-269.{/ref} In 1970 the researchers estimated there were 61 million missing women; by 2015, 136 million. This is more than the ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/grapher/population-by-country-gapminder+un?tab=chart&time=1800..2019&country=MEX",
                        "children": [
                            {
                                "text": "population of Mexico",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". We see that more than 80% are missing from China and India \u2013 68 and 45 million, respectively.",
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                ],
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                "value": [
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                        "text": "The authors also provided projections of the number of missing women through demographic changes to 2050 which you ",
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                    },
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                        "url": "https://ourworldindata.org/grapher/global-number-of-missing-women",
                        "children": [
                            {
                                "children": [
                                    {
                                        "text": "find here",
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                                    }
                                ],
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                        "text": ".",
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            {
                "type": "html",
                "value": "<div class=\"raw-html-table__container\"><table><thead><tr><th scope=\"col\" colspan=\"1\">Source</th><th scope=\"col\" colspan=\"1\">Year estimate is for</th><th scope=\"col\" colspan=\"1\">Number of missing women</th></tr></thead><tbody><tr><td colspan=\"1\" rowspan=\"1\">Sen (1990, 1992)</td><td colspan=\"1\" rowspan=\"1\">1990</td><td colspan=\"1\" rowspan=\"1\">More than 100 million</td></tr><tr><td colspan=\"1\" rowspan=\"1\">Coale (1991)</td><td colspan=\"1\" rowspan=\"1\">1990</td><td colspan=\"1\" rowspan=\"1\">60 million</td></tr><tr><td colspan=\"1\" rowspan=\"1\">Klasen (1994)</td><td colspan=\"1\" rowspan=\"1\">1990</td><td colspan=\"1\" rowspan=\"1\">92 million</td></tr><tr><td colspan=\"1\" rowspan=\"1\">Klasen and Wink (2002)</td><td colspan=\"1\" rowspan=\"1\">1990s</td><td colspan=\"1\" rowspan=\"1\">102 million</td></tr><tr><td colspan=\"1\" rowspan=\"1\">Hudson &amp; Den Boer (2004)</td><td colspan=\"1\" rowspan=\"1\">2000s</td><td colspan=\"1\" rowspan=\"1\">90 million</td></tr><tr><td colspan=\"1\" rowspan=\"1\">Guilmoto (2012)</td><td colspan=\"1\" rowspan=\"1\">2010</td><td colspan=\"1\" rowspan=\"1\">117 million</td></tr><tr><td colspan=\"1\" rowspan=\"1\">Bongaarts &amp; Guilmoto (2015)</td><td colspan=\"1\" rowspan=\"1\">2015</td><td colspan=\"1\" rowspan=\"1\">136 million</td></tr></tbody></table></div>",
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                "url": "https://ourworldindata.org/grapher/global-number-of-missing-women?time=earliest..2015",
                "type": "chart",
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            {
                "text": [
                    {
                        "text": "How many girls and women are missing every year?",
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                ],
                "type": "heading",
                "level": 3,
                "parseErrors": []
            },
            {
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                "value": [
                    {
                        "text": "Above are estimates of the total number of missing women in the world. But how many are 'missing' each year?",
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                ],
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                "type": "text",
                "value": [
                    {
                        "text": "In this chart we see estimates of (1) the number of 'missing' female births from prenatal sex discrimination; and (2) excess female deaths as a result of postnatal discrimination.{ref}Bongaarts, J., & Guilmoto, C. Z. (2015). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=doi.org%2F10.1111%2Fj.1728-4457.2015.00046.x&btnG=",
                        "children": [
                            {
                                "text": "How many more missing women? Excess female mortality and prenatal sex selection, 1970\u20132050",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". Population and Development Review, 41(2), 241-269.{/ref}",
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                        "text": "3.3 million women is the estimate fo 2015 \u2013 approximately half of which were missing births and half of which are attributed to excess female mortality. After the 1970s sex-selective abortions (shown as missing births) became more common. Until 1980, nearly all missing women were the result of excess female mortality; by 2015 as many were from missing births each year.",
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                "url": "https://ourworldindata.org/grapher/missing-female-births-and-excess-mortality",
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                "text": [
                    {
                        "text": "Why is there a preference for a son in some places?",
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                "value": [
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                        "text": "In countries where there is a clear imbalance in sex ratio, there's preference for a boy. But why does this preference exist?",
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                "value": [
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                        "text": "Son preference is most common in countries across East and South Asia, but also in some countries in the Middle East and North Africa.{ref}Hesketh, T., Lu, L., & Xing, Z. W. (2011). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "http://www.cmaj.ca/content/183/12/1374",
                        "children": [
                            {
                                "text": "The consequences of son preference and sex-selective abortion in China and other Asian countries",
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                        "spanType": "span-link"
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                        "text": ". ",
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                        "children": [
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                                "text": "CMAJ",
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                        "text": ", 183(12), 1374-1377.{/ref} Although there are significant cultural, economic and societal differences between these countries there are important parallels which explain strong preference for a boy.",
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                        "text": "What these countries tend to have in common is a strong logic of 'patrilineality': the logic that productive assets move through the male line within the family.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., & Hwa-Ok, B. (2003). ",
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                    {
                        "url": "https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=doi.org%2F10.1080%2F00220380412331293807&btnG=",
                        "children": [
                            {
                                "text": "Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea",
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                        "text": ". ",
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                        "children": [
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                                "text": "The Journal of Development Studies",
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                        "text": ", 40(2), 153-187.{/ref} Although many other countries also have patrilineality to some degree, in countries with a strong preference for a son, researchers find this logic to be much more rigid. The social order of families resides with the males: lineage is passed from father to son. Men within the social order are the fixed points, and women the moving points: when a daughter marries, she leaves the current family to join a new one.",
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                        "text": "This can produce\u00a0economic and social benefits to having a son rather than a daughter, including:",
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                                                "text": "Family name",
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                            {
                                "text": ": the lineage within a family stays within the male line. Having a son therefore continues the family name.",
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                                                "text": "Old age support",
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                                "spanType": "span-bold"
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                            {
                                "text": ": sons within a family are often responsible for supporting parents in illness and old age.{ref}Hesketh, T., Lu, L., & Xing, Z. W. (2011). ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "http://www.cmaj.ca/content/183/12/1374",
                                "children": [
                                    {
                                        "text": "The consequences of son preference and sex-selective abortion in China and other Asian countries",
                                        "spanType": "span-simple-text"
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                            {
                                "text": ". ",
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                            {
                                "children": [
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                                        "text": "CMAJ",
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                                "text": ", 183(12), 1374-1377.{/ref} Elderly parents often live with married children and overwhelmingly so with their sons. This provides a strong economic incentive for a son for old age support. It's a key differentiating factor between countries with and without strong son preference: in Taiwan, it's rare for parents to live with a married daughter, but in the Philippines (without strong son preference) parents are equally likely to live with the son or daughter.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., & Hwa-Ok, B. (2003). ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=doi.org%2F10.1080%2F00220380412331293807&btnG=",
                                "children": [
                                    {
                                        "text": "Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". ",
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                            {
                                "children": [
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                                        "text": "The Journal of Development Studies",
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                            {
                                "text": ", 40(2), 153-187.{/ref}",
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                                "children": [
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                                        "children": [
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                                                "text": "Dowries",
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                                        ],
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                                "text": ": a dowry \u2013 the transfer of property or money from the bride's to the groom's family \u2013 is an important economic concern for having a daughter. Studies in India have suggested that a dowry is the most common reason for not wanting a girl.{ref}Diamond\u2010Smith, N., Luke, N., & McGarvey, S. (2008). ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://www.tandfonline.com/doi/full/10.1080/13691050802061665",
                                "children": [
                                    {
                                        "text": "\u2018Too many girls, too much dowry\u2019: son preference and daughter aversion in rural Tamil Nadu, India",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
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                            {
                                "text": ". ",
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                            {
                                "children": [
                                    {
                                        "text": "Culture, Health & Sexuality",
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                            {
                                "text": ", 10(7), 697-708.{/ref} Even when parents themselves didn't have a dowry in their own marriage, many carry the expectation of having to provide one for a daughter, or asking for one from a future daughter-in-law. ",
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                                "children": [
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                                                "text": "Labor force opportunities",
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                            {
                                "text": ": males can bring better economic opportunities for a family. This can be the result of real sex differences in economic opportunities, but also results from undervaluing the work of women. In many countries, unpaid or informal work ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://ourworldindata.org/female-labor-supply#informal-work-unpaid-care-work",
                                "children": [
                                    {
                                        "text": "accounts for a majority share",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": " of female employment. In this sense, informal employment is often seen simply as an extension of a women's domestic work rather than being valued in its own right.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., & Hwa-Ok, B. (2003). ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=doi.org%2F10.1080%2F00220380412331293807&btnG=",
                                "children": [
                                    {
                                        "text": "Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea",
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                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". ",
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                            {
                                "children": [
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                                        "text": "The Journal of Development Studies",
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                            {
                                "text": ", 40(2), 153-187.{/ref}",
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                        "type": "text",
                        "value": [
                            {
                                "children": [
                                    {
                                        "children": [
                                            {
                                                "text": "Family and societal pressure",
                                                "spanType": "span-simple-text"
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                                        ],
                                        "spanType": "span-italic"
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                                ],
                                "spanType": "span-bold"
                            },
                            {
                                "text": ": it's not just economic concerns that parents worry about: surveys also reveal persistent pressures from family members and communities. In interviews, women often note pressures from female in-laws and husbands, verbal and physical abuse when they didn't produce a son or were pregnant with a girl.{ref}Puri, S., Adams, V., Ivey, S., & Nachtigall, R. D. (2011). ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://www.sciencedirect.com/science/article/pii/S0277953611000700",
                                "children": [
                                    {
                                        "text": "\u201cThere is such a thing as too many daughters, but not too many sons\u201d: A qualitative study of son preference and fetal sex selection among Indian immigrants in the United States",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". ",
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                            {
                                "children": [
                                    {
                                        "text": "Social Science & Medicine",
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                                "spanType": "span-italic"
                            },
                            {
                                "text": ", 72(7), 1169-1176.{/ref}",
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                                                "text": "Religion",
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                                ],
                                "spanType": "span-bold"
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                                "text": ": in some cultures it's believed that only a son can light the funeral pyre and carry out death-related rites and rituals needed for salvation.{ref}Tandon, S. L., & Sharma, R. (2006). ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://www.sascv.org/ijcjs/snehlata.pdf",
                                "children": [
                                    {
                                        "text": "Female Foeticide and Infanticide in India: An Analysis of Crimes against Girl Children",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "children": [
                                    {
                                        "text": "International Journal of Criminal Justice Sciences",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-italic"
                            },
                            {
                                "text": ", 1(1).{/ref}",
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                            }
                        ],
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                ],
                "parseErrors": []
            },
            {
                "type": "horizontal-rule",
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            {
                "text": [
                    {
                        "text": "What are the consequences of a skewed sex ratio?",
                        "spanType": "span-simple-text"
                    }
                ],
                "type": "heading",
                "level": 1,
                "parseErrors": []
            },
            {
                "type": "horizontal-rule",
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                "type": "text",
                "value": [
                    {
                        "text": "Across several countries in Asia, and North Africa we see highly skewed sex ratios in favour of males. Strong preference for sons has led to an increasing number of \"missing women\" and therefore an \"excess of males\".",
                        "spanType": "span-simple-text"
                    }
                ],
                "parseErrors": []
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            {
                "type": "text",
                "value": [
                    {
                        "text": "There are a number of adverse consequences which could result from highly imbalanced numbers of men and women in society. These present a risk to men, women, family structures and society as a whole.",
                        "spanType": "span-simple-text"
                    }
                ],
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            },
            {
                "type": "text",
                "value": [
                    {
                        "text": "The obvious consequence of gender imbalance is a large number of unmarriageable men.{ref}Hesketh, T. (2011). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.sciencedirect.com/science/article/pii/S0378378211002763",
                        "children": [
                            {
                                "text": "Selecting sex: The effect of preferring sons",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Early Human Development",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 87(11), 759-761.{/ref} A lack of women of marriageable age could have several impacts on marriage dynamics for men:{ref}Guilmoto, C. Z. (2007). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://pdfs.semanticscholar.org/b1e7/3587d7bce7cec908286fba3f3c0b32257566.pdf",
                        "children": [
                            {
                                "text": "Sex-ratio imbalance in Asia: Trends, consequences and policy responses",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Paris: LPED/IRD",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ".{/ref}",
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                ],
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                        "value": [
                            {
                                "text": "many men will have to delay marriage;",
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                        "type": "text",
                        "value": [
                            {
                                "text": "this will have a knock-on impact on younger men: not only will they be impacted by a skewed sex ratio for their generation, but will also have a 'backlog' of men from the previous generation in the 'marriage market';",
                                "spanType": "span-simple-text"
                            }
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                        "type": "text",
                        "value": [
                            {
                                "text": "a significant number of men will have to forego marriage altogether;",
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                        "type": "text",
                        "value": [
                            {
                                "text": "the poorest men will likely be most highly impacted by this \u2013 it's hypothesised that women will \"marry up\" in society, leaving the men with least resources disproportionately affected;",
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                        "value": [
                            {
                                "text": "one of the most common reasons for son preference is for family lineage (the passing down of the family name through males in the family) \u2013 this will likely not occur in families where sons do not marry.",
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                        "text": "Whilst we might assume that this dynamic would favour women, they could also suffer negative consequences:",
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                        "type": "text",
                        "value": [
                            {
                                "text": "a women's value may be increasingly lie in her role as a wife, daughter-in-law or mother. This may deny her alternative pathways, such as remaining single or becoming more career-oriented;",
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                            }
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                        "type": "text",
                        "value": [
                            {
                                "text": "women may feel increased pressure or incentives to marry or have children earlier in life (possibly closing off different economic or labour opportunities);",
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                        "type": "text",
                        "value": [
                            {
                                "text": "women may be at increased risk of violence (emotional, sexual or physical) or trafficking.{ref}Hudson, V. M., & Den Boer, A. (2005). ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://kar.kent.ac.uk/11409/1/WW-missingwomen-05.pdf",
                                "children": [
                                    {
                                        "text": "Missing women and bare branches: gender balance and conflict",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "children": [
                                    {
                                        "text": "Environmental Change and Security Program Report",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-italic"
                            },
                            {
                                "text": ", (11), 20-24.{/ref}",
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                            }
                        ],
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                ],
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                "type": "text",
                "value": [
                    {
                        "text": "Imbalanced gender ratios could have negative consequences for both men and women. For society more broadly, there are several hypotheses that it will also result in more crime, violence and disorder in communities. The rationale being that not only will there be an excess of men who do not marry and have their own family, but that the most affected will be those of lowest socioeconomic status, the most uneducated and with fewer opportunities.",
                        "spanType": "span-simple-text"
                    }
                ],
                "parseErrors": []
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            {
                "type": "text",
                "value": [
                    {
                        "text": "Hudson and De Boer (2004) propose that this situation will result in significant social stability and security concerns.{ref}Hudson, V. M., & Den Boer, A. (2005). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://kar.kent.ac.uk/11409/1/WW-missingwomen-05.pdf",
                        "children": [
                            {
                                "text": "Missing women and bare branches: gender balance and conflict",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Environmental Change and Security Program Report",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", (11), 20-24.{/ref} Although studies have found correlation between the prevalence of violence and more imbalanced gender ratios, it's difficult to disentangle a causal effect.{ref}Diamond-Smith, N., & Rudolph, K. (2018). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0197516",
                        "children": [
                            {
                                "text": "The association between uneven sex ratios and violence: Evidence from 6 Asian countries",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "PLoS One",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 13(6), e0197516.{/ref} Other researchers suggest that the evidence does not support this concern: that rather than showing through aggression and violence, excluded men will be more marginalised, lonely and at risk of psychological problems.{ref}Hesketh, T. (2011). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.sciencedirect.com/science/article/pii/S0378378211002763",
                        "children": [
                            {
                                "text": "Selecting sex: The effect of preferring sons",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Early Human Development",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 87(11), 759-761.{/ref} What's clear is that the persistence of imbalanced sex ratios means there will be demographic consequences for many decades to come.",
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                    }
                ],
                "parseErrors": []
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                "type": "horizontal-rule",
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                "text": [
                    {
                        "text": "What affects the strength of gender bias?",
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                ],
                "type": "heading",
                "level": 1,
                "parseErrors": []
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            {
                "type": "horizontal-rule",
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            {
                "text": [
                    {
                        "text": "Are richer and more educated parents less likely to have gender preference?",
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                    }
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                "level": 2,
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                "value": [
                    {
                        "text": "If our aim is to address the issue of a skewed sex ratio and female discrimination, an obvious question to ask is: will development fix the problem? Is it the case that son preference is restricted to those at lower incomes, therefore the problem disappear if ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://owid.cloud/extreme-poverty",
                        "children": [
                            {
                                "text": "poverty",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": " falls and societies develop?",
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                "value": [
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                        "text": "The evidence to date suggests, no: development on its own does not address it.",
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                "value": [
                    {
                        "text": "Studies which have looked in detail at the extent of sex ratio imbalances by demographic (comparing income level, education, literacy, employment factors amongst others) often conclude the opposite: that richer, urban families tend to discriminate more than the poor.{ref}Filmer, D., Friedman, J., & Schady, N. (2008). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://elibrary.worldbank.org/doi/abs/10.1596/1813-9450-4716",
                        "children": [
                            {
                                "text": "Development, modernization, and son preference in fertility decisions",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "The World Bank",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ".{/ref} For example, in North India higher castes (who tend to be richer) had more skewed sex ratios than lower castes.{ref}Gupta, M. D. (1987). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.jstor.org/stable/1972121",
                        "children": [
                            {
                                "text": "Selective discrimination against female children in rural Punjab, India",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Population and Development Review",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 13(1), 77-100.{/ref} Narrowing in on specific districts and household in India and South Korea suggested that it is richer families who show greater discrimination.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., & Hwa-Ok, B. (2003). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=doi.org%2F10.1080%2F00220380412331293807&btnG=",
                        "children": [
                            {
                                "text": "Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "The Journal of Development Studies",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 40(2), 153-187.{/ref}",
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                ],
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                "type": "text",
                "value": [
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                        "text": "Despite rising incomes and development across many countries in Asia, North Africa and Eastern Europe, the sex ratio got worse, not better. An important driver which may link the increase in sex ratio with development and rising incomes is fertility rates. As we show in our entry on ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://owid.cloud/fertility-rate",
                        "children": [
                            {
                                "text": "fertility rates",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
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                        "text": ", there is a very strong impact of improving development and falling fertility. And falling fertility rates in turn play a key role in exacerbating gender preference. This is often called the 'fertility squeeze'.",
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                        "children": [
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                                "text": "In smaller families, you're less likely to have a son by chance",
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                        "text": "Imagine you have five or six children: there's a very high chance that at least one of them will be a boy. For five children, there's around a 98% chance you'll have a son.{ref}To calculate this, we need to calculate the probability that in having 5 children, we have five girls. Because the 'natural' sex ratio at birth is around 105 boys per 100 girls, the probability of having a girl at each birth is slightly lower than half: it's around 47.6%. To calculate the probability of having 5 girls, we then do 0.476^5 = 0.0245 [or 2.45%]. The probability that you have at least one boy is therefore 100% - 2.45% = 97.6%.{/ref} Now imagine you have only one or two children: the likelihood you have a son is much smaller. If you have only one child, you're chances of having a son are just over half (52%); if you have two children, the odds are 77%.{ref}Since the 'natural' sex ratio at birth is around 105 boys per 100 girls, the odds of having a boy are slightly higher than having a girl: 52%. To calculate the odds of having a boy when you have two children, we start by calculating the probability of having two girls. The probability of having a girl at each birth is 47.6% [100/105 * 100]. The probability of two births producing two girls is then calculated as 0.476^2 = 0.227 [22.7%]. The odds that one is a boy is therefore 100% - 22.7% = 77%.{/ref}",
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                "value": [
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                        "text": "In many countries across the world, this ",
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                    },
                    {
                        "url": "https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=CHN+IND+KOR",
                        "children": [
                            {
                                "text": "transition happened",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
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                    {
                        "text": ": in India, average fertility rates ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=IND",
                        "children": [
                            {
                                "text": "fell from almost 6 to 2 children per woman",
                                "spanType": "span-simple-text"
                            }
                        ],
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                    },
                    {
                        "text": "; in China from over ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=CHN",
                        "children": [
                            {
                                "text": "6 down to 1.2 children",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
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                    {
                        "text": "; in South Korea from over ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=KOR",
                        "children": [
                            {
                                "text": "6 to just under one child per woman",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". As countries got richer; education levels increased; women gained more rights to education labour participation and healthcare decisions; fertility rates fell rapidly.",
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                "value": [
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                        "text": "But the result is that if you really want a son, your chances of having one naturally are now much lower. For parents of fewer children with a strong son preference, a sex-selective abortion becomes therefore a much more important option.",
                        "spanType": "span-simple-text"
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                ],
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            {
                "text": [
                    {
                        "text": "Evidence from India",
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                "type": "heading",
                "level": 3,
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                "value": [
                    {
                        "text": "Seema Jayachandran (2017) tried to quantify how much of the skew in sex ratio in India might be attributed to the decline of the fertility rate in the country.{ref}Jayachandran, S. (2017). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://pubs.aeaweb.org/doi/pdfplus/10.1257/app.20150576",
                        "children": [
                            {
                                "text": "Fertility decline and missing women",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "American Economic Journal: Applied Economics",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", 9(1), 118-39.{/ref} In this visualization we summarize results from this research, through three charts:",
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                ],
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            {
                "type": "list",
                "items": [
                    {
                        "type": "text",
                        "value": [
                            {
                                "children": [
                                    {
                                        "text": "Left chart",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-bold"
                            },
                            {
                                "text": ": we see the percentage of respondents of a survey in India who said they would prefer a son when given a hypothetical family size (number of children) from one to five i.e. having only one child; two children etc.{ref}The survey was actually posed to mothers and fathers of what they would want for their own children (who were all in secondary school at the time of the of survey). Asking it of a future hypothetical scenario helps to avoid hindsight bias.{/ref} Here we see that if they were having only one child, more than 80% of both mothers and fathers would prefer a son. This preference rapidly declines when they are asked about additional children; in fact, in the scenarios in which parents already have some sons parents preferred to have daughters.{ref}The reason for a switch to daughters is not totally clear. It's suggested having daughters within larger families is preferred to provide care for others in the family and the household. It may also be the case that a larger number of sons creates tension and conflict with regards to resource allocation.{/ref} These results suggest that parents have a very strong preference to have a son if they have a small family.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
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                    {
                        "type": "text",
                        "value": [
                            {
                                "children": [
                                    {
                                        "text": "Middle chart",
                                        "spanType": "span-simple-text"
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                                ],
                                "spanType": "span-bold"
                            },
                            {
                                "text": ": in red we see that the ",
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                            },
                            {
                                "children": [
                                    {
                                        "text": "desired fertility rate",
                                        "spanType": "span-simple-text"
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                                ],
                                "spanType": "span-italic"
                            },
                            {
                                "text": " \u2013 the number of children a woman desires to have \u2013 has declined in India in recent decades. At the same time, the child sex ratio \u2013 the number of males per 100 females \u2013 increased. The dashed line here shows the estimated change in sex ratio which results from falling fertility rates alone.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
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                        "type": "text",
                        "value": [
                            {
                                "children": [
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                                        "text": "Right chart",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-bold"
                            },
                            {
                                "text": ": the blue line shows how the child sex ratio has increased over time. Shown in grey is the estimated increase in the sex ratio which can be attributed solely to the decline in fertility rates.",
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                            }
                        ],
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                        "text": "Seema Jayachandran (2017) results suggest that between one-third and one-half of the change in sex ratio in India since 1981 can be attributed to the decline in fertility rates. Or in other words: If there had been no change in fertility rates over time, there would still be a skew in the sex ratio. But fertility declines have had a significant impact on exacerbating son preference.",
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                "text": [
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                        "text": "Development drives factors which can both increase and decrease gender preference",
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                        "text": "Disentangling a clear relationship between development and changes in the sex ratio is difficult because better education and rising incomes can impact aspects of gender selection in opposing ways.",
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                        "text": "The reason is that the skewed sex ratio not only the result from the gender preference alone, but crucially also the ability to act upon it \u2013 by having a sex-selective abortion, for example. Kashyap and Villavicencio (2016) suggest that sex-selection practices result from three conditions being met:{ref}Kashyap, R., & Villavicencio, F. (2016). ",
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                        "url": "https://link.springer.com/article/10.1007/s13524-016-0500-z",
                        "children": [
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                                "text": "The dynamics of son preference, technology diffusion, and fertility decline underlying distorted sex ratios at birth: A simulation approach",
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                        "text": ". ",
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                                "text": "Demography",
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                        "text": ", 53(5), 1261-1281.{/ref}",
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                                        "text": "willingness",
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                                ],
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                            },
                            {
                                "text": " to consider sex selection because you have a gender preference;",
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                                "text": " to act upon it through access to prenatal sex-determination screening and abortion services;",
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                                "text": " to act upon it to get the desired sex preferences within the family.",
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                        "text": "How these three conditions change with development, education, and rising incomes can be in conflict. For example, research results suggest that higher education of the parents means a lower preference for a son.{ref}Jayachandran, S. (2017). ",
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                        "url": "https://pubs.aeaweb.org/doi/pdfplus/10.1257/app.20150576",
                        "children": [
                            {
                                "text": "Fertility decline and missing women",
                                "spanType": "span-simple-text"
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                        "spanType": "span-link"
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                    {
                        "text": ". ",
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                        "children": [
                            {
                                "text": "American Economic Journal: Applied Economics",
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                        "text": ", 9(1), 118-39.{/ref} But, increased education is also associated with falling fertility rates and this decline in fertility (the 'fertility squeeze') increases son preference, as we explored above. Education therefore has two counteracting effects on the sex ratio: education decreases the ",
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                        "text": " for gender preference, but increases the\u00a0",
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                        "text": " for influencing sex preferences within the family.",
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                        "text": "Development also affects condition (2): the ability to act upon gender preference. It is often the case that richer, urban families have greater access to technologies which would allow for sex identification during pregnancy, and also a safer abortion. Poorer families in rural areas may not have this opportunity, despite having strong son preference. As they get richer, these opportunities may become available to them.",
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                        "text": "Kashyap and\u00a0Villavicencio (2017) tried to model how the changes in\u00a0",
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                        "text": ",\u00a0",
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                                "text": "ability",
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                        "text": ", and\u00a0",
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                                "text": "readiness",
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                        "text": " all affect the change in sex ratio in specific countries.{ref}Kashyap, R., & Villavicencio, F. (2016). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://link.springer.com/article/10.1007/s13524-016-0500-z",
                        "children": [
                            {
                                "text": "The dynamics of son preference, technology diffusion, and fertility decline underlying distorted sex ratios at birth: A simulation approach",
                                "spanType": "span-simple-text"
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                        "text": ". ",
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                        "children": [
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                                "text": "Demography",
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                        "text": ", 53(5), 1261-1281.{/ref} They found that even very low levels of son preference can have a significant impact on the sex ratio if sex-selection technology diffuses steadily and fertility declines quickly. This means that in contexts where economic development is fast \u2013 meaning fertility rates fall quickly and prenatal screening technologies become widely accessible \u2013 even very small levels of son preference across a population can have a significant impact on the overall sex ratio.",
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                        "text": "The relationship between development and sex ratio is complex and non-linear: what's clear is that the issue does not quickly disappear through economic development alone.",
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                "text": [
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                        "text": "Does banning prenatal practices reduce sex-selective abortion?",
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                        "text": "One of the three conditions for sex-selection is the ",
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                                "text": "ability",
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                        "text": " to act upon gender practices through access to technology.",
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                        "text": "Prenatal sex selection (PSS) relies on two technologies: prenatal sex determination (the ability to determine the sex of a foetus during pregnancy) and selective abortion.",
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                        "text": "This raises the question of whether policies that aim to regulate prenatal sex determination and abortion have an impact on the prevalence of sex selection.",
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                        "text": "Several governments limited prenatal sex selection through regulation when it became clear that sex selection was common and increasing. South Korea, China and India all implemented sex-selective abortion bans. Were they successful?",
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                        "text": "Much of the literature on the topic suggests the bans alone were not effective enough to address the problem.{ref}Gupta, M. D. (2016). ",
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                    {
                        "url": "https://paa.confex.com/paa/2016/mediafile/ExtendedAbstract/Paper1728/banning%20prenatal%20sex-selection%20PAA%202016.pdf",
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                                "text": "Is banning sex-selection the best approach for reducing prenatal discrimination?",
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                        "text": ". In ",
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                    {
                        "children": [
                            {
                                "text": "Population Association of America meeting",
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                        "text": ", Washington DC.{/ref}{ref}Subramanian, S. V., & Selvaraj, S. (2009). ",
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                    },
                    {
                        "url": "https://jech.bmj.com/content/63/3/245.short",
                        "children": [
                            {
                                "text": "Social analysis of sex imbalance in India: before and after the implementation of the Pre-Natal Diagnostic Techniques (PNDT) Act",
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                        "text": ". ",
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                        "children": [
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                                "text": "Journal of Epidemiology & Community Health",
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                        "text": ", 63(3), 245-252.{/ref}",
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                        "text": "Looking at how the sex ratio at birth changed pre- and post-ban in each country also does not suggest that they were very effective. ",
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                                "text": "South Korea",
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                        "text": "\u00a0enacted a ban on prenatal sex identification in 1987/88. At this point the sex ratio at birth was around 110 male per 100 female births \u2013 as we see in the chart here. Following the introduction of the ban, the sex ratio continued to increase \u2013 reaching over 115 males per 100 female births in 1990 and maintaining a high ratio through the early 1990s.",
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                        "text": "For ",
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                                "text": "China",
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                        "text": " the evidence is similar.\u00a0in 1994 \u2013 as part of its Law on Maternal and Infant Health Care \u2013 China introduced a ban of prenatal sex determination. As we see in this chart, the sex ratio at birth continued to increase after the introduction of the ban. In 1993 the ratio was 114 male per 100 female births; by the early 2000s this had increased to 118:100.",
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                        "text": "introduced the Pre-Conception and Pre-Natal Diagnostic Techniques Act (PNDT) in 1994 which prohibited sex selection practices, including pre-screening to determine the sex of a fetus. In the decade which followed the introduction of the act, the sex ratio at birth did not improve.",
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                "url": "https://ourworldindata.org/grapher/sex-ratio-at-birth-males-chao-et-al",
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                        "text": "At first glance, this would suggest that the banning of sex-selection practices was unsuccessful. The sex ratio continued to increase after their implementation.",
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                        "text": "Whilst researchers agree that bans alone were not effective enough to stop the practice, many acknowledge that we don't know the counterfactual scenario without a ban.{ref}Gupta, M. D. (2016). Is banning sex-selection the best approach for reducing prenatal discrimination?. In ",
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                                "text": "Population Association of America meeting",
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                        "text": ", Washington DC.{/ref} Without a ban the sex ratio might have increased even further. Some studies have argued that bans were effective in preventing a worsening of gender imbalance, even if they didn't reduce it.{ref}Nandi, A., & Deolalikar, A. B. (2013). Does a legal ban on sex-selective abortions improve child sex ratios? Evidence from a policy change in India. Journal of Development Economics, 103, 216-228.{/ref}",
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                        "text": "These policies may have had some impact on reducing the increase, but they clearly did not come close to ending the practice.",
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                        "text": "Definitions",
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                                "text": "Sex ratio at birth",
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                    {
                        "text": ": the number of males born per 100 females.",
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                                "text": "'Expected' sex ratio at birth",
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                        "text": ": the expected sex ratio at birth is not completely equal: under ordinary circumstances we would expect there to be slightly more boys born than girls. This means that in all countries, births are male-biased. The ",
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                        "children": [
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                                "text": "expected sex ratio is approximately 105 boys born per 100 girls",
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                        "text": ". This is the ",
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                                "text": "'natural' sex ratio reported by the World Health Organization",
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                        "text": " (WHO). There can be some variability in this expected ratio, ranging from around 102 to 107 boys per 100 girls. Having a male-biased sex ratio at birth therefore doesn't necessarily represent gender discrimination, although much more skewed ratios (above 107 boys per 100 girls) does suggest the use of gender selection practices.",
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                                "text": "Prenatal sex selection",
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                        "text": ": prenatal sex selection practices are those which are used to discriminate based on gender ",
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                                "text": "during a woman's pregnancy",
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                        "text": ". This requires the use of prenatal screening practices which can determine the sex of the fetus \u2013 this is often referred to as ",
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                        "children": [
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                                "text": "prenatal detection (PD)",
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                        "text": ". This is followed by abortion in the case that it isn't the desired sex.",
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                                "text": "Postnatal sex selection",
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                        "text": ": postnatal sex selection is the discrimination based on gender\u00a0",
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                        "children": [
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                                "text": "after the child has been born",
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                        "text": ". Postnatal sex selection can occur either directly through selective infanticide, or indirectly from the premature death of girls due to maltreatment, neglect or unequal treatment.",
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                                "text": "Infanticide",
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                    {
                        "text": ":\u00a0infanticide\u00a0(or infant homicide) is the intentional killing of infants.",
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                        "text": "Data Sources",
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                        "text": "World Bank",
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                                "text": " World Bank \u2013 World Development Indicators",
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                                        "text": "Description of available measures:",
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                                "text": " 1962-2017",
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                                "text": " Global, by country",
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                            {
                                "url": "http://data.worldbank.org/data-catalog/world-development-indicators",
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                                        "text": "http://data.worldbank.org/data-catalog/world-development-indicators",
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                "text": [
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                        "text": "Chao et al. (2019)",
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[
    "Hannah Ritchie"
]
 How does the number of men and women differ between countries? And why? 2019-10-28 18:08:35 2023-05-14 17:45:38 https://ourworldindata.org/wp-content/uploads/2019/06/sex-ratio-at-birth-2.png 
{}
 This article was first published in June 2019. The ratio between the number of males and females in a society is referred to as the gender ratio. This ratio is not stable but instead shaped by biological, social, technological, cultural, and economic forces. And in turn the gender ratio itself has an impact on society, demography, and the economy. In this entry we provide an overview of the variation and the changes of the gender ratio across the world. We study how it changes from birth to late life; the forces that change the ratio of men to women. Many argue persuasively that the terms 'gender' and 'sex' are not to be used interchangeably.{ref}Pryzgoda, J., & Chrisler, J. C. (2000). Definitions of gender and sex: The subtleties of meaning. _Sex Roles_, _43_(7-8), 553-569.{/ref} In this context here we have however decided to make an exception: we speak of the 'gender ratio' because it's the established term and it will help all those who want to be informed about this topic and search this term. But we also speak of the 'sex ratio' because this is arguably the more accurate term and it is increasingly used within the academic literature. **[See all interactive charts on gender ratio ↓](#all-charts)** --- # Gender Ratio across the world --- ## What share of the population is male and female? The sex ratio – the share of the population that is female – varies across the world. And globally in 2020 the share of women in the world was just under 50%. There are three reasons why the sex ratio of populations varies and is rarely equal: * differences in mortality rates and life expectancy for women and men. Women, on average, [live longer than men](https://owid.cloud/why-do-women-live-longer-than-men). This means that all else being equal, we would expect females to account for slightly more than half of the total population. * sex ratios at birth are not equal. In all countries, there are more male than female births (the extent of which varies by country as we will see below). This means that all else being equal, we would expect males to account for slightly more than half of the total population. * migration can also affect the sex ratio of the population. If in some countries there is a significant amount of imported male-dominant labour, all else being equal, we would expect males to account for more than half of the total population. The magnitude and balance of these factors determines the sex ratio of the total population. In the map we see the sex ratio of populations: this is shown as the percentage of the total population which is female. Countries over 50 percent (shown in blue) have more females than males; those below 50 percent (shown in red) have fewer females. Most countries have a female share of the population between 49 and 51 percent (within one percentage point of parity). There are however a few notable outliers: * across several countries in South and East Asia – most notably India and China – there are significantly fewer females than males. These are countries where there are large differences in sex ratio at birth. * in several countries across the Middle East there are many more males than females: in Oman, women are outnumbered 3-to-1; in the United Arab Emirates (UAE) it's almost 4-to-1. If we look at how this has changed over time (click on the country to see this), we see the share of the population that is female has declined from a ratio close to parity decades ago. The primary reason for this is a large male migrant stock: in 2017, 45 percent of the Oman and 88 percent of the UAE population were from immigration.{ref}United Nations, Department of Economic and Social Affairs, Population Division (2017). [International Migration Report 2017](http://www.un.org/en/development/desa/population/migration/publications/migrationreport/docs/MigrationReport2017_Highlights.pdf) (ST/ESA/SER.A/403).{/ref} The UN reports that only 16 and 25 percent of international migrants to Oman and UAE, respectively, were female. * there are significantly more females than males in Eastern Europe. Populations in Eastern Europe have some of the largest gaps in life expectancy between men and women: in Russia in 2021, for example, the life expectancy at birth for men was only around 64 years compared to around 75 years for women. <Chart url="https://ourworldindata.org/grapher/share-population-female"/> --- # Gender Ratio at birth and through the life course --- ## How does the sex ratio at birth vary across the world? Across the world there are differences in the sex ratio at different life stages. This imbalance in the male and female population can in some cases be traced back to birth: in some countries the number of boys and girls born each year is significantly skewed. In the map we see the differences in sex ratio at birth across the world. Here the sex ratio is measured as the number of male births for every 100 female births; a value greater than 100 indicates there are more boys than girls born that year. A figure of 110 would indicate that there are 110 male births for every 100 female births. The first striking point is that in every single country of the world there are more boys born than girls. This has been true for all years for which we have data (as far back as 1950) in all countries of the world, as you can when you move the timeslider below the map further back. Does this mean every country selects for boys prior to birth; for example, through induced abortion practices which preferentially select for boys? Not necessarily. In the absence of selective abortion practices, births in a given population are typically male-biased – the chances of having a boy are very slightly higher than having a girl. <Chart url="https://ourworldindata.org/grapher/sex-ratio-at-birth"/> ### Why are births naturally expected to be male-biased? For most countries, there are around 105 males per 100 female births. This is what the World Health Organization (WHO) estimates as the ['expected' sex ratio](https://ourworldindata.org/gender-ratio#definitions) at birth: in the absence of gender discrimination or interference we'd expect there to be around 105 boys born per 100 girls, although this can range from around 103 to 107 boys per 100 girls. Why is this? In the most comprehensive study of its kind, Orzack et al. (2015) monitored the trajectory of sex ratio from conception through to birth across five different methods.{ref}Orzack, S. H., Stubblefield, J. W., Akmaev, V. R., Colls, P., Munné, S., Scholl, T., … & Zuckerman, J. E. (2015). [The human sex ratio from conception to birth](https://pdfs.semanticscholar.org/3986/f62b66ee8450859909e122fb2974c1c9fe6b.pdf). _Proceedings of the National Academy of Sciences_, 112(16), E2102-E2111.{/ref} This produced the largest dataset available on the sex ratio throughout the stages of pregnancy. A key result from this study was that the sex ratio at conception is equal: there is no difference in the number of males and females conceived. For births to be consistently male-biased, there must be gender differences in the probability of miscarriage through pregnancy. The study found that although the probability of miscarriage varies between genders across the course of a pregnancy, female mortality is slightly higher than male mortality over the full period: * there is a higher probability that an embryo with chromosomal abnormalities{ref}In the paper the authors differentiate between 'karyotypically normal' and 'karyotypically abnormal'. This refers to whether there are mutations in chromosomes, such as an extra, missing or irregular portion of chromosomal DNA. 'karyotypically abnormal' embryos have a lower probability of surviving to birth, or often lead to other human diseases/conditions.{/ref} is male – in the first week of pregnancy, excess male mortality therefore means pregnancy is female-biased; * in the next 10-15 weeks of pregnancy female mortality is higher, which increases the ratio in favor of males; * male and female mortality is approximately equal around week 20; * between weeks 28-35 of pregnancy, there is higher male mortality. Overall, a male-biased sex ratio at birth is the result. ### In some countries the sex ratio is skewed beyond the expected sex ratio Some male-bias in births is what we expect with no deliberate gender selection through parents or society more broadly. There are, however, some key outliers in the world today: in countries including China, India, Vietnam, Pakistan, and Azerbaijan this ratio is very skewed. Here it's likely that deliberate selection practices explain part of the high sex ratio as we explore **[here](https://ourworldindata.org/gender-ratio#biology-or-discrimination-which-countries-have-skewed-sex-ratios-at-birth)**. ## The sex ratio varies with birth order Most countries have a [sex ratio at birth](https://ourworldindata.org/gender-ratio#sex-ratio-at-birth) which is around the [expected range of 105 boys born for every 100 girls](https://ourworldindata.org/gender-ratio#definitions). There are exceptions to this: there are countries – most notably in Asia – with highly skewed sex ratios in favor of males. The preference in some countries for a son is seen in the overall sex ratio at birth figures above. But this bias is even stronger when we look at how this ratio is affected by the birth order of children. In this visualization we look at the case of India and how sex ratios change from the 1st child in a family through to the 2nd, 3rd, 4th, and 5th born children. This is adapted from the _Economic Survey 2018_{ref}Jaitley, A. (2018). _[Economic Survey 2017-18: Volume I, Chapter 7: Gender and Son Meta-Preference: Is Development Itself an Antidote?](https://ideas.repec.org/p/ess/wpaper/id12445.html)_{/ref} and based on data from the DHS and National Family Health Surveys in India. It presents this data in two cases: * when the child _is not_ the last child born (i.e. the parents have additional children afterwards) – this is shown in the charts on the left; * when the child _is_ the last child born in the family (i.e. the parents stop having children afterwards) – this is shown on the right. Let's first focus on the top row, which presents the data for India as a whole. On the left-hand side we have the sex ratio at birth when the child _is not_ the last. For the 1st children, the sex ratio is very close to what we would expect 'naturally': a ratio of around 105 boys per 100 girls. But we see that for the 2nd, 3rd, 4th and 5th born children, this ratio is skewed towards girls. Remember again that this is the case when it's not the last child i.e. the parents go on to have another. In other words this shows us that when a girl is born, parents are more likely to have another child. It is evidence that parents are continuing to have children until they get a son. Compare this to the right-hand side where we see the sex ratio when the child _is_ the last. These ratios are much more skewed towards boys. Parents whose 1st child is a son are much more likely to stop having children. The sex ratio here is 182 boys per 100 girls. This is consistent across the birth order: whether it's the 2nd, 3rd, 4th or 5th child, a family is much more likely to stop having children when they have a boy. Combined we see a strong preference for a son in India: parents are more likely to continue having more children when the child is a girl and they are more likely to stop having children when they have a boy. Now compare these ratios to that of Indonesia in the second row below. Sex ratios here do not diverge strongly from the expected ratio of 105, and there is no clear difference when the child is or isn't the last to be born. Parental choices do not point to a strong preference for a son or a daughter. In the third row we see that within India there are large differences in son preference across different states. The data shows that there are states with 'weaker' and 'stronger' preference for a son. <Image filename="Sex-ratio-at-birth-by-order.png" alt=""/> ### Sex selection practices also became more prominent for later births From the study presented above we see that the sex of a child can, in some countries, be an important deciding factor for when parents stop having children. But birth order also influences the likelihood of prenatal sex selection (PSS) i.e. sex-selective abortion. We see evidence of this across several countries. Researchers looked at Indian national survey data from 1976 to 2005 to see how the sex of children and birth order affects the use of prenatal selection.{ref}Gellatly, C., & Petrie, M. (2017). [Prenatal sex selection and female infant mortality are more common in India after firstborn and second-born daughters](https://jech.bmj.com/content/71/3/269). _Journal of Epidemiology & Community Health_, 71(3), 269-274.{/ref} They found a significant and increasing skew in the sex ratio since the 1980s – a time when the [average woman in India had five children](https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=IND). This was mainly a result of male selection for the 2nd or 3rd child within a family. When the firstborn or the first- and second-born siblings were female then a boy was much more likely the 2nd or 3rd child. This skewed ratio can only be explained from prenatal sex selection in favor of boys. At a local level, a study of a large Delhi hospital known for maternal care showed very similar results.{ref}Manchanda, S., Saikia, B., Gupta, N., Chowdhary, S., & Puliyel, J. M. (2011). [Sex ratio at birth in India, its relation to birth order, sex of previous children and use of indigenous medicine](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0020097). _PLoS One_, 6(6), e20097. {/ref} The overall sex ratio was male-biased with only 806 girls per 1000 boys. But this got significantly worse when the family already had a daughter: 720 girls per 1000 boys if there was one previous girl and only 178 girls per 1000 boys for two previous daughters. Even for women who had not practiced sex-selection abortion, more mothers who had previously had a girl reported taking traditional medicines (which were ineffective) for sex selection purposes. These examples are of course not restricted to India. Many countries across Asia in particular have similar findings. In this chart we see how the sex ratio in South Korea was affected by birth order. Here we see a very steep rise in the sex ratio of third-, fourth- and later children through the 1980s. By the early 1990s there were more than 200 boys per 100 girls for third-born children; for fourth-born or higher, the ratio was close to 250:100. This occurred at a time the [number of children per woman was falling quickly](https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=KOR): in 1970 its fertility rate was 4.3 children per woman; by 1990 this had fallen to 1.6. South Korea's sex ratio has fallen back to close to natural levels over the past few decades. You can also view the data for China, by using the "change country" button in the top-left of the chart. Clearly sex ratios in China have also been affected by birth order.{ref}Jiang, Q., Yu, Q., Yang, S., & Sánchez-Barricarte, J. J. (2017). [Changes in sex ratio at birth in china: a decomposition by birth order](https://www.cambridge.org/core/services/aop-cambridge-core/content/view/51D48C611E5176A042FF28684041D997/S0021932016000547a.pdf/changes_in_sex_ratio_at_birth_in_china_a_decomposition_by_birth_order.pdf). _Journal of Biosocial Science_, 49(6), 826-841.{/ref} Here we see that since 1980 –a period in the middle of a rapid [reduction from 4 to 2 children per woman](https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=CHN) – there has been some rise in the male bias for first-born children (rising from the expected 105 boys to 114 boys per 100 girls). But we see a much more significant skew in the ratio for second or third-born children. For third-born children, the ratio was 158 boys per 100 girls, suggesting a high prevalence of sex selection abortions. South Korea provides an important example where the male bias can be successfully addressed. But for several countries across Asia this looks like a major challenge: the data shows that many parents still strongly prefer a son. <Chart url="https://ourworldindata.org/grapher/sex-ratio-at-birth-by-birth-order"/> ## Sex ratio in childhood Sex ratios – the ratio of males and females – at birth is male-biased across every country in the world; in [our section on this](https://ourworldindata.org/gender-ratio#sex-ratio-at-birth), we explain why biologically we'd expect this to be the case. The so-called ['expected' sex ratio at birth](https://ourworldindata.org/gender-ratio#definitions) was around 105 males per 100 females. But how does this ratio look later in childhood? Does it change from newborns to five-years-olds? In the two charts here we see two perspectives: firstly a global map of the sex ratio at five years old. Just as with the sex ratio at birth, we see the highest ratios in several Asian countries where the share of boys is higher than we would expect. In China, there is close to 115 boys per 100 girls at age five; in India, there are more than 109 boys per 100 girls. Secondly we see a scatterplot comparison of the sex ratio at birth (on the y-axis) versus the ratio at five years old (on the x-axis). The grey line here represents parity: a country which lies along this line has the same ratio at five years old as it does for birth. As we see, most countries lie above this line: this means the sex ratio for newborns is higher than for 5-year-olds. In other words, the male-bias tends to weaken through the first years of childhood. Why is this the case? As we explore in the next section of this entry: across most countries infant and child mortality rates are higher for boys than for girls. This means fewer boys survive the first few years of life. For most countries this results in a decline in the sex ratio. Overall we see that despite higher child mortality in boys, the sex ratio at age five in the majority of countries is over 100: this means boys still outnumber girls in childhood. <Chart url="https://ourworldindata.org/grapher/sex-ratio-at-five-years-old"/> <Chart url="https://ourworldindata.org/grapher/sex-ratio-at-birth-vs-five-years-old"/> ## Why do boys die more often than girls? From[life expectancy](https://ourworldindata.org/life-expectancy) to[ mental health](https://ourworldindata.org/mental-health);[ substance use](https://ourworldindata.org/substance-use) to[ cancer rates](https://ourworldindata.org/cancer); there are important differences in health outcomes between the sexes. In a related post, my colleague Esteban Ortiz-Ospina looks at the evidence to answer the question "[Why do women live longer than men?](https://ourworldindata.org/why-do-women-live-longer-than-men)" Here we focus on the youngest, asking, why do young boys die more often than girls? ### Child and infant mortality is higher for boys in nearly all countries Child mortality measures the share of newborns who die before reaching their 5th birthday. In the chart below we see the comparison of child mortality by sex. Here, the mortality rate for boys is shown on the y-axis, and the mortality rate for girls on the x-axis. The grey line running diagonally across the chart marks where the mortality rate for both sexes is equal. In countries which lie above the grey line, the rate for boys is higher than for girls. What's striking is that with exception of two countries – India and Tonga – child mortality is more common for boys in all countries of the world. This is also [true for infant mortality](https://ourworldindata.org/grapher/infant-mortality-by-sex), which is the share of newborns who die within their 1st year of life. We study why India and Tonga are outliers [**here**](https://ourworldindata.org/gender-ratio#infanticide-and-excess-female-mortality). Over the past half-century in particular, child mortality has been falling rapidly across the world. This has been [true for boys and girls](https://ourworldindata.org/grapher/child-mortality-line-chart-by-sex) alike. It has been known for a long time that the mortality of boys is higher. As early as 1786 the physician, Dr Joseph Clarke, read a paper to the Royal Society of London on his observations that _"mortality of males exceeds that of females in almost all stages of life, and particularly the earliest stages"_.{ref}Clarke, J., & Price, R. (1786). XVII. Observations on some causes of the excess of the mortality of males above that of females. By Joseph Clarke, MD Physician to the Lying-in Hospital at Dublin. Communicated by the Rev. Richard Price, DDFRS in a letter to Charles Blagden, MD Sec. R. S. Philosophical Transactions of the Royal Society of London, (76), 349-362.{/ref} <Chart url="https://ourworldindata.org/grapher/child-mortality-by-sex"/> ### What do infants die from? Why is it the case that boys die more often than girls? First of all, it's important to understand what young children die from. In this chart we see global mortality rates in infants across different causes in 2017. This data comes from the IHME's _Global Burden of Disease_ study, which provides estimates by sex – on the y-axis we have plotted mortality rates in boys, and on the x-axis for girls. Just like the charts above, causes which lie above the grey line are more common in boys. The chart shows that for all major causes of death, mortality is higher in boys. The sex differences in the causes of infant deaths were already documented almost a century ago: in an impressive paper published in 1929, Bawkin explores the mortality sex ratio of specific diseases from countries across the world.{ref}Bakwin, H. (1929).[ The sex factor in infant mortality](https://search.proquest.com/docview/1301822705?pq-origsite=gscholar). _Human Biology_, 1(1), 90.{/ref} There are some causes –[ HIV/AIDS](https://owid.cloud/hiv-aids), nutritional deficiencies, whooping cough, among others – for which the mortality rates are higher in girls. But overall, infant boys are more likely to die in childhood than girls.{ref}Sawyer, C. C. (2012).[ Child mortality estimation: estimating sex differences in childhood mortality since the 1970s](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1001287). _PLoS Medicine_, 9(8), e1001287.{/ref}{ref}Naeye, R. L., Burt, L. S., Wright, D. L., Blanc, W. A., & Tatter, D. (1971).[ Neonatal mortality, the male disadvantage](https://pediatrics.aappublications.org/content/48/6/902.short). _Pediatrics_, 48(6), 902-906.{/ref}{ref}This is also the explanation[ reported by](http://www.searo.who.int/entity/health_situation_trends/data/chi/sex-diff-imr/en/) the World Health Organization: "_Newborn girls have a biological advantage in survival over newborn boys. They have lesser vulnerability to perinatal conditions (including birth trauma, intrauterine hypoxia and birth asphyxia, prematurity, respiratory distress syndrome and neonatal tetanus), congenital anomalies, and such infectious diseases as intestinal infections and lower respiratory infections._"{/ref} Boys are more vulnerable in two key ways: they are at higher risk of birth complications, and infectious disease. We explore the possible reasons for this below. <Chart url="https://ourworldindata.org/grapher/infant-death-rates-by-cause-by-sex"/> ### Boys are at higher risk of birth complications From comparison of mortality rates in infant boys and girls, it becomes clear that boys are at higher risk of complications in the first few days of life: preterm births, asphyxia, birth defects and heart anomalies. But why? First of all, **boys are more likely to be born prematurely**: the share of boys born before full-term pregnancy is higher than for girls.{ref}Peelen, M. J., Kazemier, B. M., Ravelli, A. C., De Groot, C. J., Van Der Post, J. A., Mol, B. W., … & Kok, M. (2016).[ Impact of fetal gender on the risk of preterm birth, a national cohort study](https://obgyn.onlinelibrary.wiley.com/doi/pdf/10.1111/aogs.12929). _Acta obstetricia et gynecologica Scandinavica_, 95(9), 1034-1041.{/ref} This occurs naturally, but is exacerbated by the rate of induced preterm births. Boys tend to have a higher birthweight than girls – which can increase the risk of waiting to term to deliver – meaning that more boys are induced before the end of the pregnancy term.{ref}Zeitlin, J., Saurel-Cubizolles, M. J., de Mouzon, J., Rivera, L., Ancel, P. Y., Blondel, B., & Kaminski, M. (2002).[ Fetal sex and preterm birth: are males at greater risk?](https://academic.oup.com/humrep/article/17/10/2762/607779). _Human Reproduction_, 17(10), 2762-2768.{/ref} The chart above shows that more boys die from preterm births. The fact that preterm births are more common for boys contributes to this. Although boys are, on average, heavier than girls at birth, **they are less physiologically mature at birth**.This means they are at higher risk of having delayed physiological function (such as lung function) and adverse neurological outcomes.{ref}Peacock, J. L., Marston, L., Marlow, N., Calvert, S. A., & Greenough, A. (2012).[ Neonatal and infant outcome in boys and girls born very prematurely](https://www.nature.com/articles/pr201150). _Pediatric Research_, 71(3), 305.{/ref}{ref}Hintz, S. R., Kendrick, D. E., Vohr, B. R., Poole, W. K., Higgins, R. D., & Nichd Neonatal Research Network. (2006).[ Gender differences in neurodevelopmental outcomes among extremely preterm, extremely‐low‐birthweight infants](https://onlinelibrary.wiley.com/doi/abs/10.1080/08035250600599727). _Acta Paediatrica_, 95(10), 1239-1248.{/ref} For example, poorer lung function in newborn boys has been shown for both term and preterm infants.{ref}Jones, M., Castile, R., Davis, S., Kisling, J., Filbrun, D., Flucke, R., … & Tepper, R. S. (2000).[ Forced expiratory flows and volumes in infants: normative data and lung growth](https://www.atsjournals.org/doi/full/10.1164/ajrccm.161.2.9903026). _American Journal of Respiratory and Critical Care Medicine_, 161(2), 353-359.{/ref}{ref}Hoo, A. F., Henschen, M., Dezateux, C., Costeloe, K., & Stocks, J. (1998).[ Respiratory function among preterm infants whose mothers smoked during pregnancy](https://www.atsjournals.org/doi/full/10.1164/ajrccm.158.3.9711057). _American Journal of Respiratory and Critical Care Medicine_, 158(3), 700-705.{/ref} Studies have suggested that even in the case of straightforward pregnancies, lung maturation in boys lags that of girls by approximately one week.{ref}Fleisher, B., Kulovich, M. V., Hallman, M. I. K. K. O., & Gluck, L. O. U. I. S. (1985).[ Lung profile: sex differences in normal pregnancy](https://europepmc.org/abstract/med/4022494). _Obstetrics and Gynecology_, 66(3), 327-330.{/ref} These differences in maturity at birth are not restricted to lung function.{ref}Peacock, J. L., Marston, L., Marlow, N., Calvert, S. A., & Greenough, A. (2012).[ Neonatal and infant outcome in boys and girls born very prematurely](https://www.nature.com/articles/pr201150). _Pediatric Research_, 71(3), 305.{/ref} The reason for this difference has been an important question for decades – the answer is still not clear. But there are some leading hypotheses: surfactant production for lung function has been observed earlier in female fetuses, leading to improved airway flow in the lungs; estrogen has been shown to affect lung development positively in females; males, on average, have a higher birthweight meaning they may trade-off increased size for functional development; and the uterus may be less hospitable to male fetuses – the introduction of a Y chromosome in females can create an immunoreactive response to the central nervous system.{ref}DiPietro, J. A., & Voegtline, K. M. (2017).[ The gestational foundation of sex differences in development and vulnerability](https://www.sciencedirect.com/science/article/pii/S0306452215006958). _Neuroscience_, 342, 4-20.{/ref}{ref}Townsel, C. D., Emmer, S. F., Campbell, W. A., & Hussain, N. (2017).[ Gender differences in respiratory morbidity and mortality of preterm neonates](https://www.frontiersin.org/articles/10.3389/fped.2017.00006/full). _Frontiers in Pediatrics_, 5, 6.{/ref} This, combined with a higher risk of premature birth may explain why boys have higher rates of asphyxia, respiratory infections and birth defects. ### Boys are at higher risk of infectious diseases Boys are also at higher risk of infectious diseases such as syphilis,[malaria](https://owid.cloud/malaria), respiratory infections, tetanus and diarrheal diseases. This is more generally true for a broad range of infections, spanning person-to-person, vector-borne, blood-borne, and food and water borne diseases.{ref}Giefing‐Kröll, C., Berger, P., Lepperdinger, G., & Grubeck‐Loebenstein, B. (2015).[ How sex and age affect immune responses, susceptibility to infections, and response to vaccination](https://onlinelibrary.wiley.com/doi/full/10.1111/acel.12326). _Aging Cell_, 14(3), 309-321.{/ref} We see this clearly when we compare mortality rates for boys and girls in the earlier chart. But why are boys more susceptible to infection? Overall, boys have weaker immune systems. There are two key hypotheses for why. **The Y-chromosome in boys increases their vulnerability.** Biologically, males and females are differentiated by chromosomes: females have two X chromosomes (XX) and males one X and one Y chromosome (XY). Having two X chromosomes means that the newborn has a stronger immune system because X chromosomes contain a larger number of immune-related genes.{ref}Markle, J. G., & Fish, E. N. (2014).[ SeXX matters in immunity](https://www.sciencedirect.com/science/article/pii/S1471490613001592). _Trends in Immunology_, 35(3), 97-104.{/ref}{ref}Libert, C., Dejager, L., & Pinheiro, I. (2010).[ The X chromosome in immune functions: when a chromosome makes the difference](https://www.nature.com/articles/nri2815). _Nature Reviews Immunology_, 10(8), 594.{/ref} This means that, since females have two X chromosomes, they have a stronger immune response; boys on the other hand, are more vulnerable to X-linked infections.{ref}Waldron, I. (1983). Sex differences in human mortality: the role of genetic factors.[ _Social Science & Medicine_](https://www.sciencedirect.com/science/article/pii/0277953683902344), 17(6), 321-333.{/ref} This makes males more vulnerable to many infectious diseases. They are also more susceptible to specific genetic diseases where the defective genes are carried on either the X or Y chromosomes; this is because boys have only one X chromosome so a single recessive gene on that X chromosome results in the disease. But the stronger immune response of females comes with a cost. It’s the reason why women are more susceptible to autoimmune disorders such as HIV/AIDS.{ref}Libert, C., Dejager, L., & Pinheiro, I. (2010).[ The X chromosome in immune functions: when a chromosome makes the difference](https://www.nature.com/articles/nri2815). _Nature Reviews Immunology_, 10(8), 594.{/ref} **Sex hormones may be another key reason for weaker immune systems in males. **Males have much higher amounts of testosterone which seem to inhibit two major parts of the immune system – B and T-lymphocytes.{ref}Fischer, J., Jung, N., Robinson, N., & Lehmann, C. (2015).[ Sex differences in immune responses to infectious diseases](https://link.springer.com/article/10.1007/s15010-015-0791-9). _Infection_, 43(4), 399-403.{/ref} Estrogen, on the other hand, acts as an effective regulator of this. Overall, male hormones weaken the immune system relative to females. **The male disadvantage** The fact that boys are more susceptible than girls to a range of health conditions is often summarized as the “male disadvantage”. This is not restricted to childhood: the female advantage carries into adulthood. It’s part of the reason [why women tend to live longer than men](https://ourworldindata.org/why-do-women-live-longer-than-men). The leading explanations for the "male disadvantage" lie in the biological differences between the sexes. More specifically, differences in maturity, sex chromosomes, and hormones. In circumstances where both sexes are treated equally, we would therefore expect infant and child mortality rates to be slightly higher for boys. ## Sex ratio through adulthood The sex ratio – the number of males relative to females – at birth and in childhood are male-biased in almost every country. In previous discussion we covered why we'd expected this to be the case biologically. How does the sex ratio change throughout adulthood? In this chart we see the sex ratio – measured as the number of males per 100 females – at different ages through adolescence and adulthood. In the global average for adolescents and young adults we see the result of both the male-bias in birth ratios and the large impact of populous countries such as China and India with very skewed sex ratios: At age 15 and 20, males outnumber females by 106 to 100. But as we move through adulthood we see that this ratio is lower and lower. For 50-year-olds the ratio is close to 1-to-1; for 70-year-olds there are only 86 males per 100 females; and in the very oldest age bracket (people aged 100 and older) there are only 24 men per 100 women. You can explore this data for any country of region of the world using the "change country" button in the top-left of the chart. You will see that for some countries this decline in the sex ratio with age is even more extreme: in Russia, for example, by age 50 there are only 91 males per 100 females; by 70 years old there are almost twice as many women as men. In every country in the world [women tend to live longer than men](https://ourworldindata.org/grapher/life-expectancy-of-women-vs-life-expectancy-of-women). Whilst this is true today, it hasn't always been the case. In his text '[Why do women live longer than men?](https://ourworldindata.org/why-do-women-live-longer-than-men)' my colleague Esteban takes a look at the evidence and explanations for why this is the case. <Chart url="https://ourworldindata.org/grapher/sex-ratio-by-age"/> ## Why do women live longer than men? On average, women live longer than men – this is true for every country in the world. This fact plays an important role in how the sex ratio changes with age through adulthood. A detailed discussion of why this is the case is available in our explainer on '[Why do women live longer than men?](https://ourworldindata.org/why-do-women-live-longer-than-men)'. --- # Missing girls and women --- ## Biology or discrimination: which countries have skewed sex ratios at birth? Today, and at several points historically, the sex ratio at birth in some countries is too skewed to be explained by biological differences alone. The ['expected' sex ratio at birth](https://ourworldindata.org/gender-ratio#definitions) is around 105 males per 100 females. In a recent study Chao et. al (2019) re-modelled sex ratios at birth (SRB) across the world based on a range of population sources, including census and household survey data.{ref}Chao, F., Gerland, P., Cook, A.R., Alkema, L. (2019). [Systematic assessment of the sex ratio at birth for all countries and estimation of national imbalances and regional reference levels](https://www.pnas.org/content/early/2019/04/09/1812593116). _PNAS_.{/ref} The results are shown in the chart below since 1950. The authors identified 12 countries with strong statistical evidence of a skewed sex ratio: Albania, Armenia, Azerbaijan, China, Georgia, Hong Kong, India, Montenegro, South Korea, Taiwan, Tunisia, and Vietnam.{ref}Note that this does not imply that other countries do not have male preference or some evidence of a skewed sex ratio. Results of the Chao et al. (2019) study highlight those with the strongest statistical evidence of this imbalance.{/ref} <Chart url="https://ourworldindata.org/grapher/sex-ratio-at-birth-males-chao-et-al"/> Most of these countries are in Asia. Why is this the case? Is there a biological or environmental difference, or is it the result of discrimination? **Hepatitis B was proposed then later debunked** Amartya Sen was the first scholars to publicly bring attention to the concept of "missing women" as a result of sex selective abortion, unequal treatment and infanticide of girls.{ref}Sen, Amartya (20 December 1990). [More Than 100 Million Women Are Missing](https://web.archive.org/web/20130504072819/http://ucatlas.ucsc.edu/gender/Sen100M.html). _New York Review of Books_. 37 (20).{/ref} The reason for this skew in sex ratio has been previously challenged. One of the leading hypotheses was put forward by economist Emily Oster. In a 2005 paper she argued that a large proportion – approximately 45%, around 75% in China, 20-50% in Egypt and western Asia, and under 20% in India, Bangladesh, Pakistan, and Nepal – of the overrepresentation of men could be explained by the high rates of hepatitis B carriers in Asia.{ref}Oster, E. (2005). [Hepatitis B and the Case of the Missing Women](https://www.journals.uchicago.edu/doi/abs/10.1086/498588). _Journal of Political Economy_, 113(6), 1163-1216.{/ref} The rationale was that (1) hepatitis B carriers have an offspring sex ratio much more in favour of boys (1.5 boys per girl), and (2) that hepatitis B carrier rates were notably higher in Asian cultures than in the West. The combination of these two observations Oster calculated could account for a large proportion of the "missing women". A few years later, Oster debunked her own hypothesis on the role of hepatitis B in a paper titled "Hepatitis B does not explain male-biased sex ratios in China". In a study of 67,000 people in China – 15% of which were hepatitis B carriers – Oster and colleagues found no link between hepatitis B status and offspring sex ratio.{ref}Oster, E., Chen, G., Yu, X., & Lin, W. (2010). [Hepatitis B does not explain male-biased sex ratios in China](https://www.nber.org/papers/w13971). _Economics Letters_, 107(2), 142-144.{/ref} The hepatitis carrier status of neither the mother or the father had an effect on the offspring sex: carriers were not more likely to have a boy than non-carriers. The authors concluded that hepatitis B rates could not explain the skewed sex ratio in China. Other studies – such as that by Lin and Luoh (2008) in Taiwan – have also found minimal to no effect of hepatitis B on the sex ratio.{ref}Lin, M. J., & Luoh, M. C. (2008). [Can hepatitis B mothers account for the number of missing women? Evidence from three million newborns in Taiwan](https://www.jstor.org/stable/29730171). _American Economic Review_, 98(5), 2259-73.{/ref}{ref}Monica Das Gupta, [Can Biological Factors Like Hepatitis B Explain the Bulk of Gender Imbalance in China? A Review of the Evidence](https://academic.oup.com/wbro/article-abstract/23/2/201/1662748), _The World Bank Research Observer_, Volume 23, Issue 2, Fall 2008, Pages 201–217.{/ref} **Sex-selective abortions and discrimination against girls** After the hepatitis B hypothesis was debunked, no clear evidence of a biological factor in such skewed sex ratios has emerged. There is some variability in the ["expected" sex ratio](https://ourworldindata.org/gender-ratio#definitions) which may result from biological or environmental factors – a figure of 105 boys per 100 girls is usually adopted, but often this can vary from 103 to 107 boys per 100 girls. But the natural variability of the sex ratio is too small to explain the high ratios in some countries. The evidence for sex-selective abortion and discrimination against girls is now strong across several countries. Not only does the increase in sex ratios coincide with the availability of prenatal sex determination technologies, there is also clear evidence from studies investigating the use and promotion of such methods. In India, for example, prenatal diagnosis (PD) became available in the 1970s, shortly after legalization of medical abortion in 1971.{ref}Madan, K., & Breuning, M. H. (2014). [Impact of prenatal technologies on the sex ratio in India: an overview](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4052431/). _Genetics in Medicine_, 16(6), 425.{/ref} Whilst its use was intended for detection of abnormalities, it was soon used and promoted by the Indian medical profession for sex determination.{ref}Sharma, B. R., Gupta, N., & Relhan, N. (2007). [Misuse of prenatal diagnostic technology for sex-selected abortions and its consequences in India](https://www.sciencedirect.com/science/article/pii/S0033350607000960). _Public Health_, 121(11), 854-860.{/ref} Even after its use for sex determination was prohibited, studies suggest many gynecologists did not consider sex-selection abortion to be unethical and argued that it was an important intervention to balance population control with the desire for sons.{ref}Correspondent, L. I. (1983). [Misuse of amniocentesis](https://www.ncbi.nlm.nih.gov/pubmed/11644254). _Lancet_, 321, 812-813.{/ref} Results from some of the earliest studies on abortions following the availability of prenatal sex determination are striking. Over the year from 1976 to 1977, at an urban hospital in India, 96% of the girls who were tested were aborted; in contrast, all of the 250 boys tested – including those with an identified risk of genetic defect – were born.{ref}Ramanamma, A., & Bambawale, U. (1980). [The mania for sons: an analysis of social values in South Asia](https://www.sciencedirect.com/science/article/pii/0160798780900599). _Social Science & Medicine. Part B: Medical Anthropology_, 14(2), 107-110.{/ref} At a clinic in Mumbai, all of the 15,914 abortions after sex determination in 1984/85 were girls. Results from another six hospitals in the city found 7,999 of the 8,000 aborted fetuses in 1988 were girls.{ref}Tandon SL, Sharma R. (2006). [Female foeticide and infanticide in India: an analysis of crimes against girl children](http://www.sascv.org/ijcjs/previousissues.html). _International Journal of Criminal Justice Science_.{/ref} The evidence that highly skewed sex ratios at birth have been largely the result of gender discrimination and selective abortions has been well-established across several countries. We discuss the reasons for this discrimination [**here**](https://ourworldindata.org/gender-ratio#why-is-there-preference-for-a-son). There are some additional hypotheses as to why the sex ratio at birth is skewed in some countries. Based on Chinese census data, Shi and Kennedy (2016) argue that the skew in China's sex ratio is not the result of selective abortion practices, but much more the result of administrative anomalies.{ref}Shi, Y., & Kennedy, J. J. (2016). [Delayed registration and identifying the “missing girls” in China](https://www.cambridge.org/core/journals/china-quarterly/article/delayed-registration-and-identifying-the-missing-girls-in-china/0759987A48A37E3D2CFE157778747E33). _The China Quarterly_, _228_, 1018-1038.{/ref} The authors argue that the one-child policy led some parents to postpone the registration of daughters (making them appear "missing"), but that they appear later in Chinese census data. A year later, Cai (2017) challenged the authors' conclusions in support of the conventional hypothesis that this is not a statistical artefact, but a real demographic  and social challenge.{ref}Cai, Y. (2017). [Missing Girls or Hidden Girls? A Comment on Shi and Kennedy's “Delayed Registration and Identifying the ‘Missing Girls’ in China”](https://www.cambridge.org/core/journals/china-quarterly/article/missing-girls-or-hidden-girls-a-comment-on-shi-and-kennedys-delayed-registration-and-identifying-the-missing-girls-in-china/61E21855F8A1D958660973841BBC46FD). _The China Quarterly_, _231_, 797-803.{/ref} ## Infanticide Sex discrimination can occur prenatally (in the form of sex-selective abortions, as we discuss [**here**](https://ourworldindata.org/gender-ratio#biology-or-discrimination-which-countries-have-skewed-sex-ratios-at-birth)) or postnatally when it can lead to the death of a child in the very worst cases. The death of a child due to sex discrimination can be brought about in a deliberate killing of an infant (infanticide) or can be caused by neglect or poor and unequal treatment. Over time, prenatal discrimination has increased as both abortions and sex determination technologies have become more readily available. Nonetheless, postnatal discrimination still occurs and has a long history. ### **Infanticide has a long history** Infanticide (or infant homicide) – the deliberate killing of newborns and infants – has a long history.{ref}Moseley, K. L. (1985).[ The history of infanticide in Western society](https://heinonline.org/HOL/LandingPage?handle=hein.journals/ilmed1&div=42&id=&page=). _Issues in Law & Medicine_, 1, 345.{/ref}{ref}Levittan, M. (2012). The history of infanticide: exposure, sacrifice, and femicide. _Violence and Abuse in Society. Understanding a Global Crisis_. Santa Barbara, ABC-CLIO, 83-130.{/ref} From hunter-gatherers to ancient civilizations to the present day: infanticide has spanned all periods of history. In fact, anthropologist Laila Williamson goes as far to say: “Infanticide has been practiced on every continent and by people on every level of cultural complexity, from hunter gatherers to high civilizations, including our own ancestors. Rather than being an exception, then, it has been the rule."{ref}Williamson, Laila (1978). "Infanticide: an anthropological analysis". In Kohl, Marvin (ed.). _Infanticide and the Value of Life_. NY: [Prometheus Books](https://en.wikipedia.org/wiki/Prometheus_Books). pp. 61–75.{/ref} And humans are not alone. From birds to rodents; fish to mammals; we find evidence of infanticide across the animal kingdom.{ref}Hausfater, G., & Hrdy, S. B. (2017). _Infanticide: comparative and evolutionary perspectives_. Routledge.{/ref} There are some common misconceptions today surrounding the practice of infanticide. Although the term is now often adopted as a synonym for ‘female infanticide’ – the killing of unwanted girls – the gender specifics and drivers of infanticide depend on context and time in history.{ref}Scott, E. (2017, June). [Unpicking a myth: the infanticide of female and disabled infants in antiquity](https://books.google.co.uk/books?hl=en&lr=&id=n98jDwAAQBAJ&oi=fnd&pg=PA143&dq=unpicking+a+myth:+the+infanticide&ots=2XS6lFMoJO&sig=AdzrpXxZR3RWGNd-qf0FducA81I#v=onepage&q=unpicking%20a%20myth%3A%20the%20infanticide&f=false). In _TRAC 2000: Proceedings of the Tenth Annual Theoretical Archaeology Conference. London 2000_ (p. 143). Oxbow Books.{/ref} ### **Historical evidence and estimates of infanticide** **A number of researchers have studied the demographic, health and cultural profiles of prehistoric societies. In rare cases they can use indirect evidence of the fossil record; but many rely on modern hunter-gatherer societies today.{ref}This of course introduces uncertainty as to how good an analogue modern hunter-gatherers are to prehistoric societies. Modern hunter-gatherer societies may have some contact and transfer with external influence. As a result, researchers often focus on societies with as little external influence as possible, for example having no nutritional, health, sanitation or technology transfer.{/ref}** Estimates for infanticide in prehistoric societies are very high. Using recent hunter-gatherer societies as a proxy, some studies suggest anywhere from 15% to 50% of newborns were killed in the first year of life.{ref}Birdsell, Joseph, B. (1986). "Some predictions for the Pleistocene based on equilibrium systems among recent hunter gatherers". In Lee, Richard & Irven DeVore (ed.). _Man the Hunter_. Aldine Publishing Co. p. 239.{/ref} Other estimates are lower, but still very high: in the range of 15-20%.{ref}Williamson, Laila (1978). "Infanticide: an anthropological analysis". In Kohl, Marvin (ed.). _Infanticide and the Value of Life_. NY: [Prometheus Books](https://en.wikipedia.org/wiki/Prometheus_Books). pp. 61–75.{/ref} Hill & Walker (2007) looked at the demographic profiles, death rates and causes of death of recent hunter-gatherers: the Hiwi group of Venezuela. They did this using census and interviews gathered over a seven year period.{ref}Hill, K., Hurtado, A. M., & Walker, R. S. (2007). [High adult mortality among Hiwi hunter-gatherers: Implications for human evolution](https://www.sciencedirect.com/science/article/pii/S0047248406002193). _Journal of Human Evolution_, _52_(4), 443-454.{/ref} They found very high rates of infant death from violence. Infant mortality rates in the past were very high – most studies suggest around a quarter of newborns did not survive the first year of life. In the Hiwi hunter-gatherers, researchers found homicide to be the second largest cause of death, accounting for 30%. They also found large sex differences: infanticide rates were four times higher for girls than boys. Other studies of modern hunter-gatherer societies analysed the sex ratio of infants to estimate the prevalence of infanticide. Very skewed sex ratio of infants is suggestive of select infanticide. In studying 86 hunter-gatherer bands across North America, South America, Africa, Asia and Australia, researchers found high levels of female infanticide across 77 of them.{ref}Divale, W. T. (1972). [Systemic population control in the middle and upper palaeolithic: Inferences based on contemporary hunter‐gatherers](https://www.tandfonline.com/doi/abs/10.1080/00438243.1972.9979534). _World Archaeology_, _4_(2), 222-243.{/ref} This is shown in the table, where there were many more young males than females in bands where infanticide was reported as ‘common’ or ‘occasional’. <div class="raw-html-table__container"><table><thead><tr><th scope="col" colspan="1">Infanticide reported as:</th><th scope="col" colspan="1">Youth sex ratio <br>(males per 100 females)</th><th scope="col" colspan="1">Adult sex ratio <br>(males per 100 females)</th><th scope="col" colspan="1">Number of hunter-gathering bands</th></tr></thead><tbody><tr><td colspan="1" rowspan="1">Common</td><td colspan="1" rowspan="1">138</td><td colspan="1" rowspan="1">105</td><td colspan="1" rowspan="1">71</td></tr><tr><td colspan="1" rowspan="1">Occasional</td><td colspan="1" rowspan="1">138</td><td colspan="1" rowspan="1">80</td><td colspan="1" rowspan="1">6</td></tr><tr><td colspan="1" rowspan="1">Not common</td><td colspan="1" rowspan="1">100</td><td colspan="1" rowspan="1">85</td><td colspan="1" rowspan="1">3</td></tr><tr><td colspan="1" rowspan="1">Not practised</td><td colspan="1" rowspan="1">94</td><td colspan="1" rowspan="1">83</td><td colspan="1" rowspan="1">6</td></tr></tbody></table></div> The practice of infanticide was not just common in prehistoric societies, but was also very common in many – but not all – ancient cultures.{ref}Langer, W. L. (1974). [Infanticide: A historical survey](https://search.proquest.com/docview/1305583868). _The Journal of Psychohistory_, _1_(3), 353.{/ref} Evidence for this exists either in the form of preserved burial remains, documented records or writings suggestive of the practice.{ref}Milner, Larry S. (2000). _Hardness of Heart / Hardness of Life: The Stain of Human Infanticide_. Lanham/New York/Oxford: University Press of America.{/ref} ### **Both sexes** are victims of infanticide It’s a common assumption that infanticide relates only to female infanticide: the killing of unwanted girls.{ref}Scott, E. (2017, June). [Unpicking a myth: the infanticide of female and disabled infants in antiquity](https://books.google.co.uk/books?hl=en&lr=&id=n98jDwAAQBAJ&oi=fnd&pg=PA143&dq=unpicking+a+myth:+the+infanticide&ots=2XS6lFMoJO&sig=AdzrpXxZR3RWGNd-qf0FducA81I#v=onepage&q=unpicking%20a%20myth%3A%20the%20infanticide&f=false). In _TRAC 2000: Proceedings of the Tenth Annual Theoretical Archaeology Conference. London 2000_ (p. 143). Oxbow Books.{/ref} But the role or direction of gender discrimination – either towards boys or girls – is context-dependent.{ref}Hughes, A. L. (1981). [Female infanticide: Sex ratio manipulation in humans](https://www.sciencedirect.com/science/article/pii/0162309581900236). _Ethology and Sociobiology_, 2(3), 109-111.{/ref} Sometimes here is no clear gender discrimination, and it occurs for both sexes. There is of course significant evidence of female-selective infanticide throughout history: we see that in the sex ratio of many hunter-gatherer societies above through to skewed ratios in Medieval England.{ref}Kellum, B. A. (1974). [Infanticide in England in the later Middle Ages](https://search.proquest.com/openview/c1ae81634e9d46b2e7402da67bc5eeef/1?pq-origsite=gscholar&cbl=1816657). _The Journal of Psychohistory_, _1_(3), 367.{/ref} Evidence of male-selective infanticide is rarer, but does exist: in a sample of 93 preindustrial culture, 9 showed evidence of female-selective, while 1 showed male-selective infanticide.{ref}Hughes, A. L. (1981). [Female infanticide: Sex ratio manipulation in humans](https://www.sciencedirect.com/science/article/pii/0162309581900236). _Ethology and Sociobiology_, 2(3), 109-111.{/ref} Even today, cases on infanticide still exist, despite being outlawed in most countries.{ref}Cecilia Lai‐wan, C., Eric, B., & Celia Hoi‐yan, C. (2006).[ Attitudes to and practices regarding sex selection in China](https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=Cecilia+Lai%E2%80%90wan%2C+C.%2C+Eric%2C+B.%2C+%26+Celia+Hoi%E2%80%90yan%2C+C.+%282006%29.+Attitudes+to+and+practices+regarding+sex+selection+in+China.+Prenatal+Diagnosis%3A+Published+in+Affiliation+With+the+International+Society+for+Prenatal+Diagnosis%2C+26%287%29%2C+610-613.&btnG=). _Prenatal Diagnosis: Published in Affiliation With the International Society for Prenatal Diagnosis_, 26(7), 610-613.{/ref} Infanticide occurs in Western countries: in some (such as the United States) boys make up a higher share of infant homicides.{ref}Porter, T., & Gavin, H. (2010). [Infanticide and neonaticide: a review of 40 years of research literature on incidence and causes](https://journals.sagepub.com/doi/abs/10.1177/1524838010371950). _Trauma, Violence, & Abuse_, _11_(3), 99-112.{/ref} But the most widely prevalent – and selection that has a significant impact on gender ratio – is female infanticide. This remains reported across countries with a strong son preference: India and China are the most documented examples.{ref}Chunkath, S. R., & Athreya, V. B. (1997). [Female infanticide in Tamil Nadu: some evidence](https://www.jstor.org/stable/4405340). _Economic and political weekly_, WS21-WS28.{/ref}{ref}Lee, B. J. (1981). [Female infanticide in China](https://www.jstor.org/stable/41298766). _Historical Reflections/Réflexions Historiques_, 163-177.{/ref} Infanticide is the most direct case of postnatal sex selection. More often overlooked is the excess mortality which results from neglect and unequal treatment of girls. This is ‘excess female mortality’ is sometimes often referred to as ‘delayed infanticide’. ## Excess female mortality **Poor treatment of girls results in increased mortality in childhood** In almost every country young boys are more likely to die in childhood than girls – as we explore [**here**](https://ourworldindata.org/gender-ratio#why-do-boys-die-more-often-than-girls), there are several biological reasons for is. But this is not true in a few counties – India is one notable example today. There, girls die more often than boys. When we compare infant (under one year old) and child (under-5s) mortality rates between boys and girls in India we see that the difference is bigger for the older age group. While infant mortality rates are approximately the same, the child mortality rate for girls is higher. Let's then focus on children rather than infants. In the chart here we see mortality rates for boys (on the y-axis) and girls (on the x-axis) for various causes in India. This data is shown for children aged 1-4 years old in 2017. Here we see that for many, death rates are significantly higher for girls. Some of these – hepatitis, measles or tuberculosis, for example – we expect to be higher for girls. But not for infections, respiratory and diarrheal diseases. Note also the much higher mortality rates for nutritional deficiencies and protein-energy malnutrition for girls. <Chart url="https://ourworldindata.org/grapher/child-deaths-by-cause-by-sex-india"/> Poorer health outcomes for girls across some countries – often in Asia and not restricted to India – has been well-documented.{ref}Million Death Study Collaborators. (2010). [Causes of neonatal and child mortality in India: a nationally representative mortality survey](https://www.sciencedirect.com/science/article/pii/S0140673610614614). _The Lancet_, 376(9755), 1853-1860.{/ref}{ref}Raj, A., McDougal, L. P., & Silverman, J. G. (2015). [Gendered effects of siblings on child malnutrition in South Asia: cross-sectional analysis of demographic and health surveys from Bangladesh, India, and Nepal](https://link.springer.com/article/10.1007/s10995-014-1513-0). _Maternal and Child Health Journal_, 19(1), 217-226.{/ref} Even for some countries where the child mortality rate remains higher in boys than for the girls, death rates for girls are still higher than would be expected. Social preference for a boy has resulted in unequal treatment of young girls in a number of ways. Studies have shown in some countries: * poorer nutrition for girls and unequal food distribution;{ref}Aurino, E. (2017). [Do boys eat better than girls in India? Longitudinal evidence on dietary diversity and food consumption disparities among children and adolescents](https://www.sciencedirect.com/science/article/pii/S1570677X16301666). _Economics & Human Biology_, 25, 99-111.{/ref} * less breastfeeding from mothers for daughters than for sons;{ref}Jayachandran, S., & Kuziemko, I. (2011). [Why do mothers breastfeed girls less than boys? Evidence and implications for child health in India](https://academic.oup.com/qje/article-abstract/126/3/1485/1854553). _The Quarterly Journal of Economics_, 126(3), 1485-1538.{/ref} * lower healthcare utilization for girls;{ref}Ghosh, N., Chakrabarti, I., Chakraborty, M., & Biswas, R. (2013). [Factors affecting the healthcare-seeking behavior of mothers regarding their children in a rural community of Darjeeling district, West Bengal](https://www.ijmedph.org/article/60?qt-sidebar_tabs=2). _International Journal of Medicine and Public Health_, 3(1).{/ref}{ref}Barcellos, S. H., Carvalho, L. S., & Lleras-Muney, A. (2014). [Child gender and parental investments in India: Are boys and girls treated differently?](https://www.aeaweb.org/articles?id=10.1257/app.6.1.157). _American Economic Journal: Applied Economics_, 6(1), 157-89.{/ref} * during pregnancy there is evidence of preferential treatment for boys with more antenatal visits and increased tetanus vaccinations.{ref}Bharadwaj, P., & Lakdawala, L. K. (2013). [Discrimination begins in the womb: Evidence of sex-selective prenatal investments](https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=Bharadwaj%2C+P.%2C+%26+Lakdawala%2C+L.+K.+%282013%29.+Discrimination+begins+in+the+womb%3A+Evidence+of+sex-selective+prenatal+investments.+Journal+of+Human+Resources%2C+48%281%29%2C+71-113.&btnG=). _Journal of Human Resources_, 48(1), 71-113.{/ref} This combination of poorer nutrition and healthcare investment can result in higher mortality rates for girls, but also to excess mortality for women in later stages of life. ## How many women are missing? The term 'missing women' was first coined by Indian economist Amartya Sen in a 1990 article; he estimated "more than 100 million women are missing".{ref}Sen, A. (1990). [More than 100 million women are missing](http://www.ouazad.com/nyustats/resources/reading-week1.pdf). _The New York Review of Books_, 37(20), 61-66.{/ref} 'Missing women' refers to the shortfall of women from the number we would expect in the absence of sex discrimination. It is the sum of women who are missing at birth (as a result of sex-selective prenatal practices such as abortion) and excess female mortality later in life (either through infanticide, child neglect or maltreatment). Many researchers have tried to calculate the number of missing women. Using sex ratios at birth, and at different ages we can compare the observed and expected values: the difference is then defined as girls and women who are missing. There are very obvious challenges in calculating this figure. For the observed sex ratio, there is the concern of how accurate the reported number of births, males and females are. The other major issue is knowing exactly what the baseline/expected ratio of males to females would be at each stage in life. For example, the ['expected' sex ratio at birth](https://ourworldindata.org/gender-ratio#definitions) is quoted as 105 male births per 100 female births. But through time and across the world, this can often vary between 103 to 107 male births per 100 female births. The combination of these measurement issues means any estimate of the number of missing women will come with fairly high uncertainty. In the table here we provide a summary of a range of estimates – note here that the year of the estimate is different for each.** **Here we see that although there is significant uncertainty in these estimates, all are within the range of over 50 million by 1990, and likely upwards of 100 million today. In the chart we see some of the most recent estimates of missing women from 1970 through to 2015 from Bongaarts & Guilmoto (2015).{ref}Bongaarts, J., & Guilmoto, C. Z. (2015). [How many more missing women? Excess female mortality and prenatal sex selection, 1970–2050](https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=doi.org%2F10.1111%2Fj.1728-4457.2015.00046.x&btnG=). _Population and Development Review_, 41(2), 241-269.{/ref} In 1970 the researchers estimated there were 61 million missing women; by 2015, 136 million. This is more than the [population of Mexico](https://ourworldindata.org/grapher/population-by-country-gapminder+un?tab=chart&time=1800..2019&country=MEX). We see that more than 80% are missing from China and India – 68 and 45 million, respectively. The authors also provided projections of the number of missing women through demographic changes to 2050 which you [**find here**](https://ourworldindata.org/grapher/global-number-of-missing-women). <div class="raw-html-table__container"><table><thead><tr><th scope="col" colspan="1">Source</th><th scope="col" colspan="1">Year estimate is for</th><th scope="col" colspan="1">Number of missing women</th></tr></thead><tbody><tr><td colspan="1" rowspan="1">Sen (1990, 1992)</td><td colspan="1" rowspan="1">1990</td><td colspan="1" rowspan="1">More than 100 million</td></tr><tr><td colspan="1" rowspan="1">Coale (1991)</td><td colspan="1" rowspan="1">1990</td><td colspan="1" rowspan="1">60 million</td></tr><tr><td colspan="1" rowspan="1">Klasen (1994)</td><td colspan="1" rowspan="1">1990</td><td colspan="1" rowspan="1">92 million</td></tr><tr><td colspan="1" rowspan="1">Klasen and Wink (2002)</td><td colspan="1" rowspan="1">1990s</td><td colspan="1" rowspan="1">102 million</td></tr><tr><td colspan="1" rowspan="1">Hudson &amp; Den Boer (2004)</td><td colspan="1" rowspan="1">2000s</td><td colspan="1" rowspan="1">90 million</td></tr><tr><td colspan="1" rowspan="1">Guilmoto (2012)</td><td colspan="1" rowspan="1">2010</td><td colspan="1" rowspan="1">117 million</td></tr><tr><td colspan="1" rowspan="1">Bongaarts &amp; Guilmoto (2015)</td><td colspan="1" rowspan="1">2015</td><td colspan="1" rowspan="1">136 million</td></tr></tbody></table></div> <Chart url="https://ourworldindata.org/grapher/global-number-of-missing-women?time=earliest..2015"/> ### How many girls and women are missing every year? Above are estimates of the total number of missing women in the world. But how many are 'missing' each year? In this chart we see estimates of (1) the number of 'missing' female births from prenatal sex discrimination; and (2) excess female deaths as a result of postnatal discrimination.{ref}Bongaarts, J., & Guilmoto, C. Z. (2015). [How many more missing women? Excess female mortality and prenatal sex selection, 1970–2050](https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=doi.org%2F10.1111%2Fj.1728-4457.2015.00046.x&btnG=). Population and Development Review, 41(2), 241-269.{/ref} 3.3 million women is the estimate fo 2015 – approximately half of which were missing births and half of which are attributed to excess female mortality. After the 1970s sex-selective abortions (shown as missing births) became more common. Until 1980, nearly all missing women were the result of excess female mortality; by 2015 as many were from missing births each year. <Chart url="https://ourworldindata.org/grapher/missing-female-births-and-excess-mortality"/> --- # Why is there a preference for a son in some places? --- In countries where there is a clear imbalance in sex ratio, there's preference for a boy. But why does this preference exist? Son preference is most common in countries across East and South Asia, but also in some countries in the Middle East and North Africa.{ref}Hesketh, T., Lu, L., & Xing, Z. W. (2011). [The consequences of son preference and sex-selective abortion in China and other Asian countries](http://www.cmaj.ca/content/183/12/1374). _CMAJ_, 183(12), 1374-1377.{/ref} Although there are significant cultural, economic and societal differences between these countries there are important parallels which explain strong preference for a boy. What these countries tend to have in common is a strong logic of 'patrilineality': the logic that productive assets move through the male line within the family.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., & Hwa-Ok, B. (2003). [Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea](https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=doi.org%2F10.1080%2F00220380412331293807&btnG=). _The Journal of Development Studies_, 40(2), 153-187.{/ref} Although many other countries also have patrilineality to some degree, in countries with a strong preference for a son, researchers find this logic to be much more rigid. The social order of families resides with the males: lineage is passed from father to son. Men within the social order are the fixed points, and women the moving points: when a daughter marries, she leaves the current family to join a new one. This can produce economic and social benefits to having a son rather than a daughter, including: * **_Family name_**: the lineage within a family stays within the male line. Having a son therefore continues the family name. * **_Old age support_**: sons within a family are often responsible for supporting parents in illness and old age.{ref}Hesketh, T., Lu, L., & Xing, Z. W. (2011). [The consequences of son preference and sex-selective abortion in China and other Asian countries](http://www.cmaj.ca/content/183/12/1374). _CMAJ_, 183(12), 1374-1377.{/ref} Elderly parents often live with married children and overwhelmingly so with their sons. This provides a strong economic incentive for a son for old age support. It's a key differentiating factor between countries with and without strong son preference: in Taiwan, it's rare for parents to live with a married daughter, but in the Philippines (without strong son preference) parents are equally likely to live with the son or daughter.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., & Hwa-Ok, B. (2003). [Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea](https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=doi.org%2F10.1080%2F00220380412331293807&btnG=). _The Journal of Development Studies_, 40(2), 153-187.{/ref} * **_Dowries_**: a dowry – the transfer of property or money from the bride's to the groom's family – is an important economic concern for having a daughter. Studies in India have suggested that a dowry is the most common reason for not wanting a girl.{ref}Diamond‐Smith, N., Luke, N., & McGarvey, S. (2008). [‘Too many girls, too much dowry’: son preference and daughter aversion in rural Tamil Nadu, India](https://www.tandfonline.com/doi/full/10.1080/13691050802061665). _Culture, Health & Sexuality_, 10(7), 697-708.{/ref} Even when parents themselves didn't have a dowry in their own marriage, many carry the expectation of having to provide one for a daughter, or asking for one from a future daughter-in-law. * **_Labor force opportunities_**: males can bring better economic opportunities for a family. This can be the result of real sex differences in economic opportunities, but also results from undervaluing the work of women. In many countries, unpaid or informal work [accounts for a majority share](https://ourworldindata.org/female-labor-supply#informal-work-unpaid-care-work) of female employment. In this sense, informal employment is often seen simply as an extension of a women's domestic work rather than being valued in its own right.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., & Hwa-Ok, B. (2003). [Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea](https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=doi.org%2F10.1080%2F00220380412331293807&btnG=). _The Journal of Development Studies_, 40(2), 153-187.{/ref} * **_Family and societal pressure_**: it's not just economic concerns that parents worry about: surveys also reveal persistent pressures from family members and communities. In interviews, women often note pressures from female in-laws and husbands, verbal and physical abuse when they didn't produce a son or were pregnant with a girl.{ref}Puri, S., Adams, V., Ivey, S., & Nachtigall, R. D. (2011). [“There is such a thing as too many daughters, but not too many sons”: A qualitative study of son preference and fetal sex selection among Indian immigrants in the United States](https://www.sciencedirect.com/science/article/pii/S0277953611000700). _Social Science & Medicine_, 72(7), 1169-1176.{/ref} * **_Religion_**: in some cultures it's believed that only a son can light the funeral pyre and carry out death-related rites and rituals needed for salvation.{ref}Tandon, S. L., & Sharma, R. (2006). [Female Foeticide and Infanticide in India: An Analysis of Crimes against Girl Children](https://www.sascv.org/ijcjs/snehlata.pdf). _International Journal of Criminal Justice Sciences_, 1(1).{/ref} --- # What are the consequences of a skewed sex ratio? --- Across several countries in Asia, and North Africa we see highly skewed sex ratios in favour of males. Strong preference for sons has led to an increasing number of "missing women" and therefore an "excess of males". There are a number of adverse consequences which could result from highly imbalanced numbers of men and women in society. These present a risk to men, women, family structures and society as a whole. The obvious consequence of gender imbalance is a large number of unmarriageable men.{ref}Hesketh, T. (2011). [Selecting sex: The effect of preferring sons](https://www.sciencedirect.com/science/article/pii/S0378378211002763). _Early Human Development_, 87(11), 759-761.{/ref} A lack of women of marriageable age could have several impacts on marriage dynamics for men:{ref}Guilmoto, C. Z. (2007). [Sex-ratio imbalance in Asia: Trends, consequences and policy responses](https://pdfs.semanticscholar.org/b1e7/3587d7bce7cec908286fba3f3c0b32257566.pdf). _Paris: LPED/IRD_.{/ref} * many men will have to delay marriage; * this will have a knock-on impact on younger men: not only will they be impacted by a skewed sex ratio for their generation, but will also have a 'backlog' of men from the previous generation in the 'marriage market'; * a significant number of men will have to forego marriage altogether; * the poorest men will likely be most highly impacted by this – it's hypothesised that women will "marry up" in society, leaving the men with least resources disproportionately affected; * one of the most common reasons for son preference is for family lineage (the passing down of the family name through males in the family) – this will likely not occur in families where sons do not marry. Whilst we might assume that this dynamic would favour women, they could also suffer negative consequences: * a women's value may be increasingly lie in her role as a wife, daughter-in-law or mother. This may deny her alternative pathways, such as remaining single or becoming more career-oriented; * women may feel increased pressure or incentives to marry or have children earlier in life (possibly closing off different economic or labour opportunities); * women may be at increased risk of violence (emotional, sexual or physical) or trafficking.{ref}Hudson, V. M., & Den Boer, A. (2005). [Missing women and bare branches: gender balance and conflict](https://kar.kent.ac.uk/11409/1/WW-missingwomen-05.pdf). _Environmental Change and Security Program Report_, (11), 20-24.{/ref} Imbalanced gender ratios could have negative consequences for both men and women. For society more broadly, there are several hypotheses that it will also result in more crime, violence and disorder in communities. The rationale being that not only will there be an excess of men who do not marry and have their own family, but that the most affected will be those of lowest socioeconomic status, the most uneducated and with fewer opportunities. Hudson and De Boer (2004) propose that this situation will result in significant social stability and security concerns.{ref}Hudson, V. M., & Den Boer, A. (2005). [Missing women and bare branches: gender balance and conflict](https://kar.kent.ac.uk/11409/1/WW-missingwomen-05.pdf). _Environmental Change and Security Program Report_, (11), 20-24.{/ref} Although studies have found correlation between the prevalence of violence and more imbalanced gender ratios, it's difficult to disentangle a causal effect.{ref}Diamond-Smith, N., & Rudolph, K. (2018). [The association between uneven sex ratios and violence: Evidence from 6 Asian countries](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0197516). _PLoS One_, 13(6), e0197516.{/ref} Other researchers suggest that the evidence does not support this concern: that rather than showing through aggression and violence, excluded men will be more marginalised, lonely and at risk of psychological problems.{ref}Hesketh, T. (2011). [Selecting sex: The effect of preferring sons](https://www.sciencedirect.com/science/article/pii/S0378378211002763). _Early Human Development_, 87(11), 759-761.{/ref} What's clear is that the persistence of imbalanced sex ratios means there will be demographic consequences for many decades to come. --- # What affects the strength of gender bias? --- ## Are richer and more educated parents less likely to have gender preference? If our aim is to address the issue of a skewed sex ratio and female discrimination, an obvious question to ask is: will development fix the problem? Is it the case that son preference is restricted to those at lower incomes, therefore the problem disappear if [poverty](https://owid.cloud/extreme-poverty) falls and societies develop? The evidence to date suggests, no: development on its own does not address it. Studies which have looked in detail at the extent of sex ratio imbalances by demographic (comparing income level, education, literacy, employment factors amongst others) often conclude the opposite: that richer, urban families tend to discriminate more than the poor.{ref}Filmer, D., Friedman, J., & Schady, N. (2008). [Development, modernization, and son preference in fertility decisions](https://elibrary.worldbank.org/doi/abs/10.1596/1813-9450-4716). _The World Bank_.{/ref} For example, in North India higher castes (who tend to be richer) had more skewed sex ratios than lower castes.{ref}Gupta, M. D. (1987). [Selective discrimination against female children in rural Punjab, India](https://www.jstor.org/stable/1972121). _Population and Development Review_, 13(1), 77-100.{/ref} Narrowing in on specific districts and household in India and South Korea suggested that it is richer families who show greater discrimination.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., & Hwa-Ok, B. (2003). [Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea](https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=doi.org%2F10.1080%2F00220380412331293807&btnG=). _The Journal of Development Studies_, 40(2), 153-187.{/ref} Despite rising incomes and development across many countries in Asia, North Africa and Eastern Europe, the sex ratio got worse, not better. An important driver which may link the increase in sex ratio with development and rising incomes is fertility rates. As we show in our entry on [fertility rates](https://owid.cloud/fertility-rate), there is a very strong impact of improving development and falling fertility. And falling fertility rates in turn play a key role in exacerbating gender preference. This is often called the 'fertility squeeze'. **In smaller families, you're less likely to have a son by chance** Imagine you have five or six children: there's a very high chance that at least one of them will be a boy. For five children, there's around a 98% chance you'll have a son.{ref}To calculate this, we need to calculate the probability that in having 5 children, we have five girls. Because the 'natural' sex ratio at birth is around 105 boys per 100 girls, the probability of having a girl at each birth is slightly lower than half: it's around 47.6%. To calculate the probability of having 5 girls, we then do 0.476^5 = 0.0245 [or 2.45%]. The probability that you have at least one boy is therefore 100% - 2.45% = 97.6%.{/ref} Now imagine you have only one or two children: the likelihood you have a son is much smaller. If you have only one child, you're chances of having a son are just over half (52%); if you have two children, the odds are 77%.{ref}Since the 'natural' sex ratio at birth is around 105 boys per 100 girls, the odds of having a boy are slightly higher than having a girl: 52%. To calculate the odds of having a boy when you have two children, we start by calculating the probability of having two girls. The probability of having a girl at each birth is 47.6% [100/105 * 100]. The probability of two births producing two girls is then calculated as 0.476^2 = 0.227 [22.7%]. The odds that one is a boy is therefore 100% - 22.7% = 77%.{/ref} In many countries across the world, this [transition happened](https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=CHN+IND+KOR): in India, average fertility rates [fell from almost 6 to 2 children per woman](https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=IND); in China from over [6 down to 1.2 children](https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=CHN); in South Korea from over [6 to just under one child per woman](https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&time=1950..2015&country=KOR). As countries got richer; education levels increased; women gained more rights to education labour participation and healthcare decisions; fertility rates fell rapidly. But the result is that if you really want a son, your chances of having one naturally are now much lower. For parents of fewer children with a strong son preference, a sex-selective abortion becomes therefore a much more important option. ### Evidence from India Seema Jayachandran (2017) tried to quantify how much of the skew in sex ratio in India might be attributed to the decline of the fertility rate in the country.{ref}Jayachandran, S. (2017). [Fertility decline and missing women](https://pubs.aeaweb.org/doi/pdfplus/10.1257/app.20150576). _American Economic Journal: Applied Economics_, 9(1), 118-39.{/ref} In this visualization we summarize results from this research, through three charts: * **Left chart**: we see the percentage of respondents of a survey in India who said they would prefer a son when given a hypothetical family size (number of children) from one to five i.e. having only one child; two children etc.{ref}The survey was actually posed to mothers and fathers of what they would want for their own children (who were all in secondary school at the time of the of survey). Asking it of a future hypothetical scenario helps to avoid hindsight bias.{/ref} Here we see that if they were having only one child, more than 80% of both mothers and fathers would prefer a son. This preference rapidly declines when they are asked about additional children; in fact, in the scenarios in which parents already have some sons parents preferred to have daughters.{ref}The reason for a switch to daughters is not totally clear. It's suggested having daughters within larger families is preferred to provide care for others in the family and the household. It may also be the case that a larger number of sons creates tension and conflict with regards to resource allocation.{/ref} These results suggest that parents have a very strong preference to have a son if they have a small family. * **Middle chart**: in red we see that the _desired fertility rate_ – the number of children a woman desires to have – has declined in India in recent decades. At the same time, the child sex ratio – the number of males per 100 females – increased. The dashed line here shows the estimated change in sex ratio which results from falling fertility rates alone. * **Right chart**: the blue line shows how the child sex ratio has increased over time. Shown in grey is the estimated increase in the sex ratio which can be attributed solely to the decline in fertility rates. Seema Jayachandran (2017) results suggest that between one-third and one-half of the change in sex ratio in India since 1981 can be attributed to the decline in fertility rates. Or in other words: If there had been no change in fertility rates over time, there would still be a skew in the sex ratio. But fertility declines have had a significant impact on exacerbating son preference. <Image filename="Fertility-impact-on-son-preference.png" alt=""/> ### Development drives factors which can both increase and decrease gender preference Disentangling a clear relationship between development and changes in the sex ratio is difficult because better education and rising incomes can impact aspects of gender selection in opposing ways. The reason is that the skewed sex ratio not only the result from the gender preference alone, but crucially also the ability to act upon it – by having a sex-selective abortion, for example. Kashyap and Villavicencio (2016) suggest that sex-selection practices result from three conditions being met:{ref}Kashyap, R., & Villavicencio, F. (2016). [The dynamics of son preference, technology diffusion, and fertility decline underlying distorted sex ratios at birth: A simulation approach](https://link.springer.com/article/10.1007/s13524-016-0500-z). _Demography_, 53(5), 1261-1281.{/ref} 0. _willingness_ to consider sex selection because you have a gender preference; 1. _ability_ to act upon it through access to prenatal sex-determination screening and abortion services; 2. _readiness_ to act upon it to get the desired sex preferences within the family. How these three conditions change with development, education, and rising incomes can be in conflict. For example, research results suggest that higher education of the parents means a lower preference for a son.{ref}Jayachandran, S. (2017). [Fertility decline and missing women](https://pubs.aeaweb.org/doi/pdfplus/10.1257/app.20150576). _American Economic Journal: Applied Economics_, 9(1), 118-39.{/ref} But, increased education is also associated with falling fertility rates and this decline in fertility (the 'fertility squeeze') increases son preference, as we explored above. Education therefore has two counteracting effects on the sex ratio: education decreases the _willingness_ for gender preference, but increases the _readiness_ for influencing sex preferences within the family. Development also affects condition (2): the ability to act upon gender preference. It is often the case that richer, urban families have greater access to technologies which would allow for sex identification during pregnancy, and also a safer abortion. Poorer families in rural areas may not have this opportunity, despite having strong son preference. As they get richer, these opportunities may become available to them. Kashyap and Villavicencio (2017) tried to model how the changes in _willingness_, _ability_, and _readiness_ all affect the change in sex ratio in specific countries.{ref}Kashyap, R., & Villavicencio, F. (2016). [The dynamics of son preference, technology diffusion, and fertility decline underlying distorted sex ratios at birth: A simulation approach](https://link.springer.com/article/10.1007/s13524-016-0500-z). _Demography_, 53(5), 1261-1281.{/ref} They found that even very low levels of son preference can have a significant impact on the sex ratio if sex-selection technology diffuses steadily and fertility declines quickly. This means that in contexts where economic development is fast – meaning fertility rates fall quickly and prenatal screening technologies become widely accessible – even very small levels of son preference across a population can have a significant impact on the overall sex ratio. The relationship between development and sex ratio is complex and non-linear: what's clear is that the issue does not quickly disappear through economic development alone. ## Does banning prenatal practices reduce sex-selective abortion? One of the three conditions for sex-selection is the _ability_ to act upon gender practices through access to technology. Prenatal sex selection (PSS) relies on two technologies: prenatal sex determination (the ability to determine the sex of a foetus during pregnancy) and selective abortion. This raises the question of whether policies that aim to regulate prenatal sex determination and abortion have an impact on the prevalence of sex selection. Several governments limited prenatal sex selection through regulation when it became clear that sex selection was common and increasing. South Korea, China and India all implemented sex-selective abortion bans. Were they successful? Much of the literature on the topic suggests the bans alone were not effective enough to address the problem.{ref}Gupta, M. D. (2016). [Is banning sex-selection the best approach for reducing prenatal discrimination?](https://paa.confex.com/paa/2016/mediafile/ExtendedAbstract/Paper1728/banning%20prenatal%20sex-selection%20PAA%202016.pdf). In _Population Association of America meeting_, Washington DC.{/ref}{ref}Subramanian, S. V., & Selvaraj, S. (2009). [Social analysis of sex imbalance in India: before and after the implementation of the Pre-Natal Diagnostic Techniques (PNDT) Act](https://jech.bmj.com/content/63/3/245.short). _Journal of Epidemiology & Community Health_, 63(3), 245-252.{/ref} Looking at how the sex ratio at birth changed pre- and post-ban in each country also does not suggest that they were very effective. **South Korea** enacted a ban on prenatal sex identification in 1987/88. At this point the sex ratio at birth was around 110 male per 100 female births – as we see in the chart here. Following the introduction of the ban, the sex ratio continued to increase – reaching over 115 males per 100 female births in 1990 and maintaining a high ratio through the early 1990s. For **China** the evidence is similar. in 1994 – as part of its Law on Maternal and Infant Health Care – China introduced a ban of prenatal sex determination. As we see in this chart, the sex ratio at birth continued to increase after the introduction of the ban. In 1993 the ratio was 114 male per 100 female births; by the early 2000s this had increased to 118:100. **India **introduced the Pre-Conception and Pre-Natal Diagnostic Techniques Act (PNDT) in 1994 which prohibited sex selection practices, including pre-screening to determine the sex of a fetus. In the decade which followed the introduction of the act, the sex ratio at birth did not improve. <Chart url="https://ourworldindata.org/grapher/sex-ratio-at-birth-males-chao-et-al"/> At first glance, this would suggest that the banning of sex-selection practices was unsuccessful. The sex ratio continued to increase after their implementation. Whilst researchers agree that bans alone were not effective enough to stop the practice, many acknowledge that we don't know the counterfactual scenario without a ban.{ref}Gupta, M. D. (2016). Is banning sex-selection the best approach for reducing prenatal discrimination?. In _Population Association of America meeting_, Washington DC.{/ref} Without a ban the sex ratio might have increased even further. Some studies have argued that bans were effective in preventing a worsening of gender imbalance, even if they didn't reduce it.{ref}Nandi, A., & Deolalikar, A. B. (2013). Does a legal ban on sex-selective abortions improve child sex ratios? Evidence from a policy change in India. Journal of Development Economics, 103, 216-228.{/ref} These policies may have had some impact on reducing the increase, but they clearly did not come close to ending the practice. --- # Definitions --- **Sex ratio at birth**: the number of males born per 100 females. **'Expected' sex ratio at birth**: the expected sex ratio at birth is not completely equal: under ordinary circumstances we would expect there to be slightly more boys born than girls. This means that in all countries, births are male-biased. The **expected sex ratio is approximately 105 boys born per 100 girls**. This is the ['natural' sex ratio reported by the World Health Organization](http://www.searo.who.int/entity/health_situation_trends/data/chi/sex-ratio/en/) (WHO). There can be some variability in this expected ratio, ranging from around 102 to 107 boys per 100 girls. Having a male-biased sex ratio at birth therefore doesn't necessarily represent gender discrimination, although much more skewed ratios (above 107 boys per 100 girls) does suggest the use of gender selection practices. **Prenatal sex selection**: prenatal sex selection practices are those which are used to discriminate based on gender _during a woman's pregnancy_. This requires the use of prenatal screening practices which can determine the sex of the fetus – this is often referred to as **prenatal detection (PD)**. This is followed by abortion in the case that it isn't the desired sex. **Postnatal sex selection**: postnatal sex selection is the discrimination based on gender _after the child has been born_. Postnatal sex selection can occur either directly through selective infanticide, or indirectly from the premature death of girls due to maltreatment, neglect or unequal treatment. **Infanticide**: infanticide (or infant homicide) is the intentional killing of infants. --- # Data Sources --- ### World Bank * **Data Source:** World Bank – World Development Indicators * **Description of available measures:** * **Time span:** 1962-2017 * **Geographical coverage:** Global, by country * **Link:**[http://data.worldbank.org/data-catalog/world-development-indicators](http://data.worldbank.org/data-catalog/world-development-indicators) ### Chao et al. (2019) * **Data Source:** Chao, F., Gerland, P., Cook, A.R., Alkema, L. (2019). Systematic assessment of the sex ratio at birth for all countries and estimation of national imbalances and regional reference levels. _PNAS_. * **Description of available measures:** * **Time span:** 1950-2017 * **Geographical coverage:** Global, by country * **Link:**[https://www.pnas.org/content/early/2019/04/09/1812593116](https://www.pnas.org/content/early/2019/04/09/1812593116) <AllCharts heading="Interactive charts on gender ratio"/> 
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        "rendered": "\n<div class=\"blog-info\">This article was first published in June 2019.</div>\n\n\n\n<p>The ratio between the number of males and females in a society is referred to as the gender ratio. This ratio is not stable but instead shaped by biological, social, technological, cultural, and economic forces. And in turn the gender ratio itself has an impact on society, demography, and the economy.</p>\n\n\n\n<p>In this entry we provide an overview of the variation and the changes of the gender ratio across the world. We study how it changes from birth to late life; the forces that change the ratio of men to women.</p>\n\n\n\n<p>Many argue persuasively that the terms &#8216;gender&#8217; and &#8216;sex&#8217; are not to be used interchangeably.{ref}Pryzgoda, J., &amp; Chrisler, J. C. (2000). Definitions of gender and sex: The subtleties of meaning.&nbsp;<em>Sex Roles</em>,&nbsp;<em>43</em>(7-8), 553-569.{/ref}</p>\n\n\n\n<p> In this context here we have however decided to make an exception: we speak of the &#8216;gender ratio&#8217; because it&#8217;s the established term and it will help all those who want to be informed about this topic and search this term. But we also speak of the &#8216;sex ratio&#8217; because this is arguably the more accurate term and it is increasingly used within the academic literature.</p>\n\n\n\t<div class=\"wp-block-owid-summary\">\n\t\t<h2>Summary</h2>\n\t\t\n\n<ul><li><a href=\"https://ourworldindata.org/gender-ratio#sex-ratio-at-birth\">The sex ratio at birth is not equal: in every country births are male-biased. There are biological reasons why there are slightly more boys born every year than girls. The &#8216;natural&#8217; sex ratio at birth is around 105 boys per 100 girls (ranging from around 103 to 107 boys).</a></li><li><a href=\"https://ourworldindata.org/gender-ratio#biology-or-discrimination-which-countries-have-skewed-sex-ratios-at-birth\">In some countries, the sex ratio at birth is much more skewed than would occur naturally. Today and in the recent past this is particularly common across Asia and North Africa. Here there is clear evidence of gender selection through prenatal sex determination and selective abortion.</a></li><li><a href=\"https://ourworldindata.org/gender-ratio#how-does-sex-ratio-vary-with-birth-order\">In countries where there is a clear son preference, the sex ratio at birth becomes increasingly skewed with birth order (the third or fourth born children are more likely to be boys than the first or second child).</a></li><li><a href=\"https://ourworldindata.org/gender-ratio#sex-ratio-in-childhood\">In nearly every country, boys are more likely to die in childhood than girls. There are biological reasons for this: boys are more susceptible to birth complications and infectious diseases.</a></li><li><a href=\"https://ourworldindata.org/gender-ratio#infanticide-and-excess-female-mortality\">In countries where there is strong son preference, mortality rates for girls are higher than would be expected: this can occur either through direct infanticide, but also through neglect and unequal treatment.</a></li><li><a href=\"https://ourworldindata.org/gender-ratio#sex-ratio-through-adulthood\">The sex ratio tends to decrease&nbsp;over the life course (from becoming male-biased to female-biased). This is because women tend to live longer than men.</a></li><li><a href=\"https://ourworldindata.org/gender-ratio#how-many-missing-women-are-there\">It&#8217;s estimated that today there are over 130 million &#8216;missing women&#8217; in the world as a result of selective abortion and excess female deaths.</a></li><li><a href=\"https://ourworldindata.org/gender-ratio#does-banning-prenatal-practices-reduce-sex-selective-abortion\">The banning of sex determination scanning and gender-selective abortion may have limited the increase in sex ratio at birth in some countries, but did not fully address the problem.</a></li><li><a href=\"https://ourworldindata.org/gender-ratio#do-richer-and-more-educated-parents-have-less-gender-bias\">Development can have opposing impacts on sex ratio: there is evidence that the son preference declines with education, but this often goes hand-in-hand with declining fertility rates and increased access to selective technologies (which can increase the sex ratio).</a></li></ul>\n\n\n\t</div>\n\n\n<h2>Gender Ratio across the world</h2>\n\n\n\n<h3>What share of the population is male and female?</h3>\n\n\n\n<p>The sex ratio \u2013 the share of the population that is female \u2013 varies across the world. And globally in 2020 the share of women in the world was just under 50%.</p>\n\n\n\n<p>There are three reasons why the sex ratio of populations varies and is rarely equal:</p>\n\n\n\n<ul><li>differences in mortality rates and life expectancy for women and men. Women, on average, <a href=\"https://owid.cloud/why-do-women-live-longer-than-men\">live longer than men</a>. This means that all else being equal, we would expect females to account for slightly more than half of the total population.</li><li>sex ratios at birth are not equal. In all countries, there are more male than female births (the extent of which varies by country as we will see below). This means that all else being equal, we would expect males to account for slightly more than half of the total population.</li><li>migration can also affect the sex ratio of the population. If in some countries there is a significant amount of imported male-dominant labour, all else being equal, we would expect males to account for more than half of the total population.</li></ul>\n\n\n\n<p>The magnitude and balance of these factors determines the sex ratio of the total population.</p>\n\n\n\n<p>In the map we see the sex ratio of populations: this is shown as the percentage of the total population which is female. Countries over 50 percent (shown in blue) have more females than males; those below 50 percent (shown in red) have fewer females.</p>\n\n\n\n<p>Most countries have a female share of the population between 49 and 51 percent (within one percentage point of parity).</p>\n\n\n\n<p>There are however a few notable outliers:</p>\n\n\n\n<ul><li>across several countries in South and East Asia \u2013 most notably India and China \u2013 there are significantly fewer females than males. These are countries where there are large differences in sex ratio at birth.</li><li>in several countries across the Middle East there are many more males than females: in Oman, women are outnumbered 3-to-1; in the United Arab Emirates (UAE) it&#8217;s almost 4-to-1. If we look at how this has changed over time (click on the country to see this), we see the share of the population that is female has declined from a ratio close to parity decades ago. The primary reason for this is a large male migrant stock: in 2017, 45 percent of the Oman and 88 percent of the UAE population were from immigration.{ref}United Nations, Department of Economic and Social Affairs, Population Division (2017). <a href=\"http://www.un.org/en/development/desa/population/migration/publications/migrationreport/docs/MigrationReport2017_Highlights.pdf\">International Migration Report 2017</a>&nbsp;(ST/ESA/SER.A/403).{/ref} The UN reports that only 16 and 25 percent of international migrants to Oman and UAE, respectively, were female. </li><li>there are significantly more females than males in Eastern Europe. Populations in Eastern Europe have some of the largest gaps in life expectancy between men and women: in Russia in 2021, for example, the life expectancy at birth for men was only around 64 years compared to around 75 years for women.</li></ul>\n\n\n\n<iframe style=\"width: 100%; height: 600px; border: 0px none;\" src=\"https://ourworldindata.org/grapher/share-population-female\"></iframe>\n\n\n\n<h2>Gender Ratio at birth and through the life course</h2>\n\n\n\n<h3>How does the sex ratio at birth vary across the world?</h3>\n\n\n\n<p>Across the world there are differences in the sex ratio at different life stages. This imbalance in the male and female population can in some cases be traced back to birth: in some countries the number of boys and girls born each year is significantly skewed.</p>\n\n\n\n<p>In the map we see the differences in sex ratio at birth across the world. Here the sex ratio is measured as the number of male births for every 100 female births; a value greater than 100 indicates there are more boys than girls born that year. A figure of 110 would indicate that there are 110 male births for every 100 female births.</p>\n\n\n\n<p>The first striking point is that in every single country of the world there are more boys born than girls. This has been true for all years for which we have data (as far back as 1950) in all countries of the world, as you can when you move the timeslider below the map further back.</p>\n\n\n\n<p>Does this mean every country selects for boys prior to birth; for example, through induced abortion practices which preferentially select for boys? Not necessarily.</p>\n\n\n\n<p>In the absence of selective abortion practices, births in a given population are typically male-biased \u2013 the chances of having a boy are very slightly higher than having a girl.</p>\n\n\n\n<figure><iframe src=\"https://ourworldindata.org/grapher/sex-ratio-at-birth\"></iframe></figure>\n\n\n\n<h4>Why are births naturally expected to be male-biased?</h4>\n\n\n\n<p>For most countries, there are around 105 males per 100 female births. This is what the World Health Organization (WHO) estimates as&nbsp;the <a href=\"https://ourworldindata.org/gender-ratio#definitions\">&#8216;expected&#8217; sex ratio</a> at birth: in the absence of gender discrimination or interference we&#8217;d expect there to be around 105 boys born per 100 girls, although this can range from around 103 to 107 boys per 100 girls.&nbsp;Why is this?</p>\n\n\n\n<p>In the most comprehensive study of its kind, Orzack et al. (2015) monitored the trajectory of sex ratio from conception through to birth across five different methods.{ref}Orzack, S. H., Stubblefield, J. W., Akmaev, V. R., Colls, P., Munn\u00e9, S., Scholl, T., \u2026 &amp; Zuckerman, J. E. (2015). <a href=\"https://pdfs.semanticscholar.org/3986/f62b66ee8450859909e122fb2974c1c9fe6b.pdf\">The human sex ratio from conception to birth</a>. <em>Proceedings of the National Academy of Sciences</em>, 112(16), E2102-E2111.{/ref}</p>\n\n\n\n<p> This produced the largest dataset available on the sex ratio throughout the stages of pregnancy.</p>\n\n\n\n<p>A key result from this study was that the sex ratio at conception is equal: there is no difference in the number of males and females conceived. For births to be consistently male-biased, there must be gender differences in the probability of miscarriage through pregnancy.</p>\n\n\n\n<p>The study found that although the probability of miscarriage varies between genders across the course of a pregnancy, female mortality is slightly higher than male mortality over the full period:</p>\n\n\n\n<ul><li>there is a higher probability that an embryo with chromosomal abnormalities{ref}In the paper the authors differentiate between &#8216;karyotypically normal&#8217; and &#8216;karyotypically abnormal&#8217;. This refers to whether there are mutations in chromosomes, such as an extra, missing or irregular portion of chromosomal DNA. &#8216;karyotypically abnormal&#8217; embryos have a lower probability of surviving to birth, or often lead to other human diseases/conditions.{/ref} is male \u2013 in the first week of pregnancy, excess male mortality therefore means pregnancy is female-biased;</li><li>in the next 10-15 weeks of pregnancy female mortality is higher, which increases the ratio in favor of males;</li><li>male and female mortality is approximately equal around week 20;</li><li>between weeks 28-35 of pregnancy, there is higher male mortality.</li></ul>\n\n\n\n<p>Overall, a male-biased sex ratio at birth is the result.</p>\n\n\n\n<h4>In some countries the sex ratio is skewed beyond the expected sex ratio</h4>\n\n\n\n<p>Some male-bias in births is what we expect with no deliberate gender selection through parents or society more broadly. There are, however, some key outliers in the world today: in countries including China, India, Vietnam, Pakistan, and Azerbaijan this ratio is very skewed. Here it&#8217;s likely that deliberate selection practices explain part of the high sex ratio as we explore <strong><a href=\"https://ourworldindata.org/gender-ratio#biology-or-discrimination-which-countries-have-skewed-sex-ratios-at-birth\">here</a></strong>.</p>\n\n\n\n<h3>The sex ratio varies with birth order</h3>\n\n\n\n<p>Most countries have a <a href=\"https://ourworldindata.org/gender-ratio#sex-ratio-at-birth\">sex ratio at birth</a> which is around the <a href=\"https://ourworldindata.org/gender-ratio#definitions\">expected range of 105 boys born for every 100 girls</a>.&nbsp;There are exceptions to this: there are countries \u2013 most notably in Asia \u2013 with highly skewed sex ratios in favor of males.</p>\n\n\n\n<p>The preference in some countries for a son is seen in the overall sex ratio at birth figures above. But this bias is even stronger when we look at how this ratio is affected by the birth order of children.</p>\n\n\n\n<p>In this visualization we look at the case of India and how sex ratios change from the 1st child in a family through to the 2nd, 3rd, 4th, and 5th born children. This is adapted from the&nbsp;<em>Economic Survey 2018</em>{ref}Jaitley, A. (2018). <em><a href=\"https://ideas.repec.org/p/ess/wpaper/id12445.html\">Economic Survey 2017-18: Volume I, Chapter 7: Gender and Son Meta-Preference: Is Development Itself an Antidote?</a></em>{/ref} and based on data from the DHS and National Family Health Surveys in India. It presents this data in two cases:</p>\n\n\n\n<ul><li>when the child <em>is not</em> the last child born (i.e. the parents have additional children afterwards) \u2013 this is shown in the charts on the left;</li><li>when the child <em>is</em> the last child born in the family (i.e. the parents stop having children afterwards) \u2013 this is shown on the right.</li></ul>\n\n\n\n<p>Let&#8217;s first focus on the top row, which presents the data for India as a whole. On the left-hand side we have the sex ratio at birth when the child <em>is not</em> the last. For the 1st children, the sex ratio is very close to what we would expect &#8216;naturally&#8217;: a ratio of around 105 boys per 100 girls. But we see that for the 2nd, 3rd, 4th and 5th born children, this ratio is skewed towards girls. Remember again that this is the case when it&#8217;s not the last child i.e. the parents go on to have another. In other words this shows us that when a girl is born, parents are more likely to have another child. It is evidence that parents are continuing to have children until they get a son.</p>\n\n\n\n<p>Compare this to the right-hand side where we see the sex ratio when the child <em>is</em> the last. These ratios are much more skewed towards boys. Parents whose 1st child is a son are much more likely to stop having children. The sex ratio here is 182 boys per 100 girls. This is consistent across the birth order: whether it&#8217;s the 2nd, 3rd, 4th or 5th child, a family is much more likely to stop having children when they have a boy.</p>\n\n\n\n<p>Combined we see a strong preference for a son in India: parents are more likely to continue having more children when the child is a girl and they are more likely to stop having children when they have a boy.</p>\n\n\n\n<p>Now compare these ratios to that of Indonesia in the second row below. Sex ratios here do not diverge strongly from the expected ratio of 105, and there is no clear difference when the child is or isn&#8217;t the last to be born.&nbsp;Parental choices do not point to a strong preference for a son or a daughter.</p>\n\n\n\n<p>In the third row we see that within India there are large differences in son preference across different states. The data shows that there are states with &#8216;weaker&#8217; and &#8216;stronger&#8217; preference for a son.</p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><a href=\"https://owid.cloud/app/uploads/2019/06/Sex-ratio-at-birth-by-order.png\"><img loading=\"lazy\" width=\"438\" height=\"550\" src=\"https://owid.cloud/app/uploads/2019/06/Sex-ratio-at-birth-by-order-438x550.png\" alt=\"\" class=\"wp-image-23711\" srcset=\"https://owid.cloud/app/uploads/2019/06/Sex-ratio-at-birth-by-order-438x550.png 438w, https://owid.cloud/app/uploads/2019/06/Sex-ratio-at-birth-by-order-119x150.png 119w, https://owid.cloud/app/uploads/2019/06/Sex-ratio-at-birth-by-order-318x400.png 318w, https://owid.cloud/app/uploads/2019/06/Sex-ratio-at-birth-by-order-768x965.png 768w\" sizes=\"(max-width: 438px) 100vw, 438px\" /></a></figure></div>\n\n\n\n<h4>Sex selection practices also became more prominent for later births</h4>\n\n\n\n<p>From the study presented above we see that the sex of a child can, in some countries, be an important deciding factor for when parents stop having children.</p>\n\n\n\n<p>But birth order also influences the likelihood of prenatal sex selection (PSS) i.e. sex-selective abortion. We see evidence of this across several countries.</p>\n\n\n\n<p>Researchers looked at Indian national survey data from 1976 to 2005 to see how the sex of children and birth order affects the use of prenatal selection.{ref}Gellatly, C., &amp; Petrie, M. (2017). <a href=\"https://jech.bmj.com/content/71/3/269\">Prenatal sex selection and female infant mortality are more common in India after firstborn and second-born daughters</a>. <em>Journal of Epidemiology &amp; Community Health</em>, 71(3), 269-274.{/ref} They found a significant and increasing skew in the sex ratio since the 1980s \u2013 a time when the <a href=\"https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=IND\">average woman in India had five children</a>. This was mainly a result of male selection for the 2nd or 3rd child within a family.&nbsp;When the firstborn or the first- and second-born siblings were female then a boy was much more likely the 2nd or 3rd child. This skewed ratio can only be explained from prenatal sex selection in favor of boys.</p>\n\n\n\n<p>At a local level, a study of a large Delhi hospital known for maternal care showed very similar results.{ref}Manchanda, S., Saikia, B., Gupta, N., Chowdhary, S., &amp; Puliyel, J. M. (2011). <a href=\"https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0020097\">Sex ratio at birth in India, its relation to birth order, sex of previous children and use of indigenous medicine</a>. <em>PLoS One</em>, 6(6), e20097. {/ref} The overall sex ratio was male-biased with only 806 girls per 1000 boys. But this got significantly worse when the family already had a daughter: 720 girls per 1000 boys if there was one previous girl and only 178 girls per 1000 boys for two previous daughters. Even for women who had not practiced sex-selection abortion, more mothers who had previously had a girl reported taking traditional medicines (which were ineffective) for sex selection purposes.</p>\n\n\n\n<p>These examples are of course not restricted to India. Many countries across Asia in particular have similar findings. In this chart we see how the sex ratio in South Korea was affected by birth order. Here we see a very steep rise in the sex ratio of third-, fourth- and later children through the 1980s. By the early 1990s there were more than 200 boys per 100 girls for third-born children; for fourth-born or higher, the ratio was close to 250:100. This occurred at a time the <a href=\"https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=KOR\">number of children per woman was falling quickly</a>: in 1970 its fertility rate was 4.3 children per woman; by 1990 this had fallen to 1.6. South Korea&#8217;s sex ratio has fallen back to close to natural levels over the past few decades.</p>\n\n\n\n<p>You can also view the data for China, by using the &#8220;change country&#8221; button in the top-left of the chart. Clearly sex ratios in China have also been affected by birth order.{ref}Jiang, Q., Yu, Q., Yang, S., &amp; S\u00e1nchez-Barricarte, J. J. (2017). <a href=\"https://www.cambridge.org/core/services/aop-cambridge-core/content/view/51D48C611E5176A042FF28684041D997/S0021932016000547a.pdf/changes_in_sex_ratio_at_birth_in_china_a_decomposition_by_birth_order.pdf\">Changes in sex ratio at birth in china: a decomposition by birth order</a>. <em>Journal of Biosocial Science</em>, 49(6), 826-841.{/ref} Here we see that since 1980 \u2013a period in the middle of a rapid <a href=\"https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=CHN\">reduction from 4 to 2 children per woman</a> \u2013 there has been some rise in the male bias for first-born children (rising from the expected 105 boys to 114 boys per 100 girls). But we see a much more significant skew in the ratio for second or third-born children. For third-born children, the ratio was 158 boys per 100 girls, suggesting a high prevalence of sex selection abortions.</p>\n\n\n\n<p>South Korea provides an important example where the male bias can be successfully addressed. But for several countries across Asia this looks like a major challenge: the data shows that many parents still strongly prefer a son.</p>\n\n\n\n<iframe style=\"width: 100%; height: 600px; border: 0px none;\" src=\"https://ourworldindata.org/grapher/sex-ratio-at-birth-by-birth-order\"></iframe>\n\n\n\n<h3>Sex ratio in childhood</h3>\n\n\n\n<p>Sex ratios \u2013 the ratio of males and females \u2013 at birth is male-biased across every country in the world; in <a href=\"https://ourworldindata.org/gender-ratio#sex-ratio-at-birth\">our section on this</a>, we explain why biologically we&#8217;d expect this to be the case. The so-called <a href=\"https://ourworldindata.org/gender-ratio#definitions\">&#8216;expected&#8217; sex ratio at birth</a> was around 105 males per 100 females. But how does this ratio look later in childhood? Does it change from newborns to five-years-olds?</p>\n\n\n\n<p>In the two charts here we see two perspectives: firstly a global map of the sex ratio at five years old. Just as with the sex ratio at birth, we see the highest ratios in several Asian countries where the share of boys is higher than we would expect. In China, there is close to 115 boys per 100 girls at age five; in India, there are more than 109 boys per 100 girls.</p>\n\n\n\n<p>Secondly we see a scatterplot comparison of the sex ratio at birth (on the y-axis) versus the ratio at five years old (on the x-axis). The grey line here represents parity: a country which lies along this line has the same ratio at five years old as it does for birth. As we see, most countries lie above this line: this means the sex ratio for newborns is higher than for 5-year-olds.</p>\n\n\n\n<p>In other words, the male-bias tends to weaken through the first years of childhood. Why is this the case? As we explore in the next section of this entry: across most countries infant and child mortality rates are higher for boys than for girls. This means fewer boys survive the first few years of life. For most countries this results in a decline in the sex ratio.</p>\n\n\n\n<p>Overall we see that despite higher child mortality in boys, the sex ratio at age five in the majority of countries is over 100: this means boys still outnumber girls in childhood.</p>\n\n\n\n<iframe style=\"width: 100%; height: 600px; border: 0px none;\" src=\"https://ourworldindata.org/grapher/sex-ratio-at-five-years-old\"></iframe>\n\n\n\n<iframe style=\"width: 100%; height: 600px; border: 0px none;\" src=\"https://ourworldindata.org/grapher/sex-ratio-at-birth-vs-five-years-old\"></iframe>\n\n\n\n<h3>Why do boys die more often than girls?</h3>\n\n\n\n<p><span style=\"font-weight: 400;\">From</span> <a href=\"https://ourworldindata.org/life-expectancy\"><span style=\"font-weight: 400;\">life expectancy</span></a><span style=\"font-weight: 400;\"> to</span><a href=\"https://ourworldindata.org/mental-health\"> <span style=\"font-weight: 400;\">mental health</span></a><span style=\"font-weight: 400;\">;</span><a href=\"https://ourworldindata.org/substance-use\"> <span style=\"font-weight: 400;\">substance use</span></a><span style=\"font-weight: 400;\"> to</span><a href=\"https://ourworldindata.org/cancer\"> <span style=\"font-weight: 400;\">cancer rates</span></a><span style=\"font-weight: 400;\">; there are important differences in health outcomes between the sexes. In a related post, my colleague Esteban Ortiz-Ospina looks at the evidence to answer the question &#8220;</span><a href=\"https://ourworldindata.org/why-do-women-live-longer-than-men\"><span style=\"font-weight: 400;\">Why do women live longer than men?</span></a><span style=\"font-weight: 400;\">&#8220;</span></p>\n\n\n\n<p><span style=\"font-weight: 400;\">Here we focus on the youngest, asking, why do young boys die more often than girls?</span></p>\n\n\n\n<h4>Child and infant mortality is higher for boys in nearly all countries</h4>\n\n\n\n<p>Child mortality measures the share of newborns who die before reaching their 5th birthday.&nbsp;In the chart below we see the comparison of child mortality by sex.</p>\n\n\n\n<p>Here, the mortality rate for boys is shown on the y-axis, and the mortality rate for girls on the x-axis. The grey line running diagonally across the chart marks where the mortality rate for both sexes is equal. In countries which lie above the grey line, the rate for boys is higher than for girls.</p>\n\n\n\n<p>What&#8217;s striking is that with exception of two countries \u2013 India and Tonga \u2013 child mortality is more common for boys in all countries of the world. This is also <a href=\"https://ourworldindata.org/grapher/infant-mortality-by-sex\">true for infant mortality</a>, which is the share of newborns who die within their 1st year of life. We study why India and Tonga are outliers <a href=\"https://ourworldindata.org/gender-ratio#infanticide-and-excess-female-mortality\"><strong>here</strong></a>.</p>\n\n\n\n<p>Over the past half-century in particular, child mortality has been falling rapidly across the world. This has been <a href=\"https://ourworldindata.org/grapher/child-mortality-line-chart-by-sex\">true for boys and girls</a> alike.</p>\n\n\n\n<p>It has been known for a long time that the mortality of boys is higher. As early as 1786 the physician, Dr Joseph Clarke, read a paper to the Royal Society of London on his observations that <em>&#8220;mortality of males exceeds that of females in almost all stages of life, and particularly the earliest stages&#8221;</em>.{ref}Clarke, J., &amp; Price, R. (1786). XVII. Observations on some causes of the excess of the mortality of males above that of females. By Joseph Clarke, MD Physician to the Lying-in Hospital at Dublin. Communicated by the Rev. Richard Price, DDFRS in a letter to Charles Blagden, MD Sec. R. S. Philosophical Transactions of the Royal Society of London, (76), 349-362.{/ref}</p>\n\n\n\n<iframe style=\"width: 100%; height: 600px; border: 0px none;\" src=\"https://ourworldindata.org/grapher/child-mortality-by-sex\"></iframe>\n\n\n\n<h4>What do infants die from?</h4>\n\n\n\n<p>Why is it the case that boys die more often than girls? First of all, it&#8217;s important to understand what young children die from.</p>\n\n\n\n<p><span style=\"font-weight: 400;\">In this chart we see global mortality rates in infants across different causes in 2017. This data comes from the IHME&#8217;s </span><i><span style=\"font-weight: 400;\">Global Burden of Disease</span></i><span style=\"font-weight: 400;\"> study, which provides estimates by sex \u2013 on the y-axis we have plotted mortality rates in boys, and on the x-axis for girls. Just like the charts above, causes which lie above the grey line are more common in boys.</span></p>\n\n\n\n<p><span style=\"font-weight: 400;\">The chart shows that for all major causes of death, mortality is higher in boys. The sex differences in the causes of infant deaths were already documented almost a century ago: in an impressive paper published in 1929, Bawkin explores the mortality sex ratio of specific diseases from countries across the world.</span>{ref}Bakwin, H. (1929).<a href=\"https://search.proquest.com/docview/1301822705?pq-origsite=gscholar\"> The sex factor in infant mortality</a>. <em>Human Biology</em>, 1(1), 90.{/ref}</p>\n\n\n\n<p><span style=\"font-weight: 400;\">There are some causes \u2013</span><a href=\"https://owid.cloud/hiv-aids\"> <span style=\"font-weight: 400;\">HIV/AIDS</span></a><span style=\"font-weight: 400;\">, nutritional deficiencies, whooping cough, among others \u2013 for which the mortality rates are higher in girls. But overall, infant boys are more likely to die in childhood than girls.</span>{ref}Sawyer, C. C. (2012).<a href=\"https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1001287\"> Child mortality estimation: estimating sex differences in childhood mortality since the 1970s</a>. <em>PLoS Medicine</em>, 9(8), e1001287.{/ref}{ref}Naeye, R. L., Burt, L. S., Wright, D. L., Blanc, W. A., &amp; Tatter, D. (1971).<a href=\"https://pediatrics.aappublications.org/content/48/6/902.short\"> Neonatal mortality, the male disadvantage</a>. <em>Pediatrics</em>, 48(6), 902-906.{/ref}{ref}This is also the explanation<a href=\"http://www.searo.who.int/entity/health_situation_trends/data/chi/sex-diff-imr/en/\"> reported by</a> the World Health Organization: &#8220;<em>Newborn girls have a biological advantage in survival over newborn boys. They have lesser vulnerability to perinatal conditions (including birth trauma, intrauterine hypoxia and birth asphyxia, prematurity, respiratory distress syndrome and neonatal tetanus), congenital anomalies, and such infectious diseases as intestinal infections and lower respiratory infections.</em>&#8220;{/ref}</p>\n\n\n\n<p><span style=\"font-weight: 400;\">Boys are more vulnerable in two key ways: they are at higher risk of birth complications, and infectious disease. We explore the possible reasons for this below.</span></p>\n\n\n\n<iframe style=\"width: 100%; height: 600px; border: 0px none;\" src=\"https://ourworldindata.org/grapher/infant-death-rates-by-cause-by-sex\"></iframe>\n\n\n\n<h4>Boys are at higher risk of birth complications</h4>\n\n\n\n<p><span style=\"font-weight: 400;\">From comparison of mortality rates in infant boys and girls, it becomes clear that boys are at higher risk of complications in the first few days of life: preterm births, asphyxia, birth defects and heart anomalies. But why?<br> <br>First of all, </span><b>boys are more likely to be born prematurely</b><span style=\"font-weight: 400;\">: the share of boys born before full-term pregnancy is higher than for girls.</span>{ref}Peelen, M. J., Kazemier, B. M., Ravelli, A. C., De Groot, C. J., Van Der Post, J. A., Mol, B. W., \u2026 &amp; Kok, M. (2016).<a href=\"https://obgyn.onlinelibrary.wiley.com/doi/pdf/10.1111/aogs.12929\"> Impact of fetal gender on the risk of preterm birth, a national cohort study</a>. <em>Acta obstetricia et gynecologica Scandinavica</em>, 95(9), 1034-1041.{/ref}&nbsp;This occurs naturally, but is exacerbated by the rate of induced preterm births. Boys tend to have a higher birthweight than girls \u2013 which can increase the risk of waiting to term to deliver \u2013 meaning that more boys are induced before the end of the pregnancy term.{ref}Zeitlin, J., Saurel-Cubizolles, M. J., de Mouzon, J., Rivera, L., Ancel, P. Y., Blondel, B., &amp; Kaminski, M. (2002).<a href=\"https://academic.oup.com/humrep/article/17/10/2762/607779\"> Fetal sex and preterm birth: are males at greater risk?</a>. <em>Human Reproduction</em>, 17(10), 2762-2768.{/ref}&nbsp;The chart above shows that more boys die from preterm births. The fact that preterm births are more common for boys contributes to this.</p>\n\n\n\n<p><span style=\"font-weight: 400;\">Although boys are, on average, heavier than girls at birth, </span><b>they are less physiologically mature at birth</b><span style=\"font-weight: 400;\">.</span> <span style=\"font-weight: 400;\">This means they are at higher risk of having delayed physiological function (such as lung function) and adverse neurological outcomes.</span>{ref}Peacock, J. L., Marston, L., Marlow, N., Calvert, S. A., &amp; Greenough, A. (2012).<a href=\"https://www.nature.com/articles/pr201150\"> Neonatal and infant outcome in boys and girls born very prematurely</a>. <em>Pediatric Research</em>, 71(3), 305.{/ref}{ref}Hintz, S. R., Kendrick, D. E., Vohr, B. R., Poole, W. K., Higgins, R. D., &amp; Nichd Neonatal Research Network. (2006).<a href=\"https://onlinelibrary.wiley.com/doi/abs/10.1080/08035250600599727\"> Gender differences in neurodevelopmental outcomes among extremely preterm, extremely\u2010low\u2010birthweight infants</a>. <em>Acta Paediatrica</em>, 95(10), 1239-1248.{/ref}&nbsp;For example, poorer lung function in newborn boys has been shown for both term and preterm infants.{ref}Jones, M., Castile, R., Davis, S., Kisling, J., Filbrun, D., Flucke, R., \u2026 &amp; Tepper, R. S. (2000).<a href=\"https://www.atsjournals.org/doi/full/10.1164/ajrccm.161.2.9903026\"> Forced expiratory flows and volumes in infants: normative data and lung growth</a>. <em>American Journal of Respiratory and Critical Care Medicine</em>, 161(2), 353-359.{/ref}{ref}Hoo, A. F., Henschen, M., Dezateux, C., Costeloe, K., &amp; Stocks, J. (1998).<a href=\"https://www.atsjournals.org/doi/full/10.1164/ajrccm.158.3.9711057\"> Respiratory function among preterm infants whose mothers smoked during pregnancy</a>. <em>American Journal of Respiratory and Critical Care Medicine</em>, 158(3), 700-705.{/ref}&nbsp;Studies have suggested that even in the case of straightforward pregnancies, lung maturation in boys lags that of girls by approximately one week.{ref}Fleisher, B., Kulovich, M. V., Hallman, M. I. K. K. O., &amp; Gluck, L. O. U. I. S. (1985).<a href=\"https://europepmc.org/abstract/med/4022494\"> Lung profile: sex differences in normal pregnancy</a>. <em>Obstetrics and Gynecology</em>, 66(3), 327-330.{/ref}&nbsp;These differences in maturity at birth are not restricted to lung function.{ref}Peacock, J. L., Marston, L., Marlow, N., Calvert, S. A., &amp; Greenough, A. (2012).<a href=\"https://www.nature.com/articles/pr201150\"> Neonatal and infant outcome in boys and girls born very prematurely</a>. <em>Pediatric Research</em>, 71(3), 305.{/ref}</p>\n\n\n\n<p><span style=\"font-weight: 400;\">The reason for this difference has been an important question for decades \u2013 the answer is still not clear. But there are some leading hypotheses: surfactant production for lung function has been observed earlier in female fetuses, leading to improved airway flow in the lungs; estrogen has been shown to affect lung development positively in females; males, on average, have a higher birthweight meaning they may trade-off increased size for functional development; and the uterus may be less hospitable to male fetuses \u2013 the introduction of a Y chromosome in females can create an immunoreactive response to the central nervous system.</span>{ref}DiPietro, J. A., &amp; Voegtline, K. M. (2017).<a href=\"https://www.sciencedirect.com/science/article/pii/S0306452215006958\"> The gestational foundation of sex differences in development and vulnerability</a>. <em>Neuroscience</em>, 342, 4-20.{/ref}{ref}Townsel, C. D., Emmer, S. F., Campbell, W. A., &amp; Hussain, N. (2017).<a href=\"https://www.frontiersin.org/articles/10.3389/fped.2017.00006/full\"> Gender differences in respiratory morbidity and mortality of preterm neonates</a>. <em>Frontiers in Pediatrics</em>, 5, 6.{/ref}</p>\n\n\n\n<p><span style=\"font-weight: 400;\">This, combined with a higher risk of premature birth may explain why boys have higher rates of asphyxia, respiratory infections and birth defects.</span></p>\n\n\n\n<h4>Boys are at higher risk of infectious diseases</h4>\n\n\n\n<p><span style=\"font-weight: 400;\">Boys are also at higher risk of infectious diseases such as syphilis,</span> <a href=\"https://owid.cloud/malaria\"><span style=\"font-weight: 400;\">malaria</span></a><span style=\"font-weight: 400;\">, respiratory infections, tetanus and diarrheal diseases. This is more generally true for a broad range of infections, spanning person-to-person, vector-borne, blood-borne, and food and water borne diseases.</span>{ref}Giefing\u2010Kr\u00f6ll, C., Berger, P., Lepperdinger, G., &amp; Grubeck\u2010Loebenstein, B. (2015).<a href=\"https://onlinelibrary.wiley.com/doi/full/10.1111/acel.12326\"> How sex and age affect immune responses, susceptibility to infections, and response to vaccination</a>. <em>Aging Cell</em>, 14(3), 309-321.{/ref}</p>\n\n\n\n<p><span style=\"font-weight: 400;\">We see this clearly when we compare mortality rates for boys and girls in the earlier chart. But why are boys more susceptible to infection?</span></p>\n\n\n\n<p><span style=\"font-weight: 400;\">Overall, boys have weaker immune systems. There are two key hypotheses for why.</span></p>\n\n\n\n<p><span style=\"font-weight: 400;\"><b>The Y-chromosome in boys increases their vulnerability.</b> Biologically, males and females are differentiated by chromosomes: females have two X chromosomes (XX) and males one X and one Y chromosome (XY). Having two X chromosomes means that the newborn has a stronger immune system because X chromosomes contain a larger number of immune-related genes.</span>{ref}Markle, J. G., &amp; Fish, E. N. (2014).<a href=\"https://www.sciencedirect.com/science/article/pii/S1471490613001592\"> SeXX matters in immunity</a>. <em>Trends in Immunology</em>, 35(3), 97-104.{/ref}{ref}Libert, C., Dejager, L., &amp; Pinheiro, I. (2010).<a href=\"https://www.nature.com/articles/nri2815\"> The X chromosome in immune functions: when a chromosome makes the difference</a>. <em>Nature Reviews Immunology</em>, 10(8), 594.{/ref}&nbsp;This means that, since females have two X chromosomes, they have a stronger immune response; boys on the other hand, are more vulnerable to X-linked infections.{ref}Waldron, I. (1983). Sex differences in human mortality: the role of genetic factors.<a href=\"https://www.sciencedirect.com/science/article/pii/0277953683902344\"> <em>Social Science &amp; Medicine</em></a>, 17(6), 321-333.{/ref}</p>\n\n\n\n<p><span style=\"font-weight: 400;\">This makes males more vulnerable to many infectious diseases. They are also more susceptible to specific genetic diseases where the defective genes are carried on either the X or Y chromosomes; this is because boys have only one X chromosome so a single recessive gene on that X chromosome results in the disease.</span></p>\n\n\n\n<p><span style=\"font-weight: 400;\">But the stronger immune response of females comes with a cost. It\u2019s the reason why women are more susceptible to autoimmune disorders such as HIV/AIDS.</span>{ref}Libert, C., Dejager, L., &amp; Pinheiro, I. (2010).<a href=\"https://www.nature.com/articles/nri2815\"> The X chromosome in immune functions: when a chromosome makes the difference</a>. <em>Nature Reviews Immunology</em>, 10(8), 594.{/ref}</p>\n\n\n\n<p><b>Sex hormones may be another key reason for weaker immune systems in males. </b><span style=\"font-weight: 400;\">Males have much higher amounts of testosterone which seem to inhibit two major parts of the immune system \u2013 B and T-lymphocytes.</span>{ref}Fischer, J., Jung, N., Robinson, N., &amp; Lehmann, C. (2015).<a href=\"https://link.springer.com/article/10.1007/s15010-015-0791-9\"> Sex differences in immune responses to infectious diseases</a>. <em>Infection</em>, 43(4), 399-403.{/ref}</p>\n\n\n\n<p><span style=\"font-weight: 400;\">Estrogen, on the other hand, acts as an effective regulator of this. Overall, male hormones weaken the immune system relative to females.</span></p>\n\n\n\n<p><strong>The male disadvantage</strong></p>\n\n\n\n<p><span style=\"font-weight: 400;\">The fact that boys are more susceptible than girls to a range of health conditions is often summarized as the \u201cmale disadvantage\u201d. This is not restricted to childhood: the female advantage carries into adulthood. It\u2019s part of the reason </span><a href=\"https://ourworldindata.org/why-do-women-live-longer-than-men\"><span style=\"font-weight: 400;\">why women tend to live longer than men</span></a><span style=\"font-weight: 400;\">. </span></p>\n\n\n\n<p><span style=\"font-weight: 400;\">The leading explanations for the &#8220;male disadvantage&#8221; lie in the biological differences between the sexes. More specifically, differences in maturity, sex chromosomes, and hormones.</span></p>\n\n\n\n<p><span style=\"font-weight: 400;\">In circumstances where both sexes are treated equally, we would therefore expect infant and child mortality rates to be slightly higher for boys.</span></p>\n\n\n\n<h3>Sex ratio through adulthood</h3>\n\n\n\n<p>The sex ratio \u2013 the number of males relative to females \u2013 at birth and in childhood are male-biased in almost every country.<br>\nIn previous discussion we covered why we&#8217;d expected this to be the case biologically.</p>\n\n\n\n<p>How does the sex ratio change throughout adulthood?</p>\n\n\n\n<p>In this chart we see the sex ratio \u2013 measured as the number of males per 100 females \u2013 at different ages through adolescence and adulthood.</p>\n\n\n\n<p>In the global average for adolescents and young adults we see the result of both the male-bias in birth ratios and the large impact of populous countries such as China and India with very skewed sex ratios: At age 15 and 20, males outnumber females by 106 to 100.</p>\n\n\n\n<p>But as we move through adulthood we see that this ratio is lower and lower. For 50-year-olds the ratio is close to 1-to-1; for 70-year-olds there are only 86 males per 100 females; and in the very oldest age bracket (people aged 100 and older) there are only 24 men per 100 women.</p>\n\n\n\n<p>You can explore this data for any country of region of the world using the &#8220;change country&#8221; button in the top-left of the chart. You will see that for some countries this decline in the sex ratio with age is even more extreme: in Russia, for example, by age 50 there are only 91 males per 100 females; by 70 years old there are almost twice as many women as men.</p>\n\n\n\n<p>In every country in the world <a rel=\"noopener noreferrer nofollow\" data-token-index=\"1\" data-reactroot=\"\" href=\"https://ourworldindata.org/grapher/life-expectancy-of-women-vs-life-expectancy-of-women\" target=\"_blank\">women tend to live longer than men</a>. Whilst this is true today, it hasn&#8217;t always been the case. In his text &#8216;<a rel=\"noopener noreferrer nofollow\" data-token-index=\"3\" data-reactroot=\"\" href=\"https://ourworldindata.org/why-do-women-live-longer-than-men\" target=\"_blank\">Why do women live longer than men?</a>&#8216; my colleague Esteban takes a look at the evidence and explanations for why this is the case.</p>\n\n\n\n<iframe style=\"width: 100%; height: 600px; border: 0px none;\" src=\"https://ourworldindata.org/grapher/sex-ratio-by-age\"></iframe>\n\n\n\n<h3>Why do women live longer than men?</h3>\n\n\n\n<p>On average, women live longer than men \u2013 this is true for every country in the world. This fact plays an important role in how the sex ratio changes with age through adulthood.</p>\n\n\n\n<p>A detailed discussion of why this is the case is available in our explainer on &#8216;<a href=\"https://ourworldindata.org/why-do-women-live-longer-than-men\">Why do women live longer than men?</a>&#8216;.</p>\n\n\n\n<h2>Missing girls and women</h2>\n\n\n\n<h3>Biology or discrimination: which countries have skewed sex ratios at birth?</h3>\n\n\n\n<p>Today, and at several points historically, the sex ratio at birth in some countries is too skewed to be explained by biological differences alone. The <a href=\"https://ourworldindata.org/gender-ratio#definitions\">&#8216;expected&#8217; sex ratio at birth</a> is around 105 males per 100 females.</p>\n\n\n\n<p>In a recent study Chao et. al (2019) re-modelled sex ratios at birth (SRB) across the world based on a range of population sources, including census and household survey data.{ref}Chao, F., Gerland, P., Cook, A.R., Alkema, L. (2019). <a href=\"https://www.pnas.org/content/early/2019/04/09/1812593116\">Systematic assessment of the sex ratio at birth for all countries and estimation of national imbalances and regional reference levels</a>. <em>PNAS</em>.{/ref} The results are shown in the chart below since 1950. The authors identified 12 countries with strong statistical evidence of a skewed sex ratio: Albania, Armenia, Azerbaijan, China, Georgia, Hong Kong, India, Montenegro, South Korea, Taiwan, Tunisia, and Vietnam.{ref}Note that this does not imply that other countries do not have male preference or some evidence of a skewed sex ratio. Results of the Chao et al. (2019) study highlight those with the strongest statistical evidence of this imbalance.{/ref}</p>\n\n\n\n<iframe style=\"width: 100%; height: 600px; border: 0px none;\" src=\"https://ourworldindata.org/grapher/sex-ratio-at-birth-males-chao-et-al\"></iframe>\n\n\n\n<p>Most of these countries are in Asia. Why is this the case? Is there a biological or environmental difference, or is it the result of discrimination?</p>\n\n\n\n<p><b>Hepatitis B was proposed then later debunked</b><br>Amartya Sen was the first scholars to publicly bring attention to the concept of &#8220;missing women&#8221; as a result of sex selective abortion, unequal treatment and infanticide of girls.{ref}Sen, Amartya (20 December 1990). <a href=\"https://web.archive.org/web/20130504072819/http://ucatlas.ucsc.edu/gender/Sen100M.html\">More Than 100 Million Women Are Missing</a>. <em>New York Review of Books</em>. 37 (20).{/ref}</p>\n\n\n\n<p>The reason for this skew in sex ratio has been previously challenged. One of the leading hypotheses was put forward by economist Emily Oster. In a 2005 paper she argued that a large proportion \u2013 approximately 45%, around 75% in China, 20-50% in Egypt and western Asia, and under 20% in India, Bangladesh, Pakistan, and Nepal \u2013 of the overrepresentation of men could be explained by the high rates of hepatitis B carriers in Asia.{ref}Oster, E. (2005). <a href=\"https://www.journals.uchicago.edu/doi/abs/10.1086/498588\">Hepatitis B and the Case of the Missing Women</a>. <em>Journal of Political Economy</em>, 113(6), 1163-1216.{/ref} The rationale was that (1) hepatitis B carriers have an offspring sex ratio much more in favour of boys (1.5 boys per girl), and (2) that hepatitis B carrier rates were notably higher in Asian cultures than in the West. The combination of these two observations Oster calculated could account for a large proportion of the &#8220;missing women&#8221;.</p>\n\n\n\n<p>A few years later, Oster debunked her own hypothesis on the role of hepatitis B in a paper titled &#8220;Hepatitis B does not explain male-biased sex ratios in China&#8221;. In a study of 67,000 people in China \u2013 15% of which were hepatitis B carriers \u2013 Oster and colleagues found no link between hepatitis B status and offspring sex ratio.{ref}Oster, E., Chen, G., Yu, X., &amp; Lin, W. (2010). <a href=\"https://www.nber.org/papers/w13971\">Hepatitis B does not explain male-biased sex ratios in China</a>. <em>Economics Letters</em>, 107(2), 142-144.{/ref} The hepatitis carrier status of neither the mother or the father had an effect on the offspring sex: carriers were not more likely to have a boy than non-carriers. The authors concluded that hepatitis B rates could not explain the skewed sex ratio in China.</p>\n\n\n\n<p>Other studies \u2013 such as that by Lin and Luoh (2008) in Taiwan \u2013 have also found minimal to no effect of hepatitis B on the sex ratio.{ref}Lin, M. J., &amp; Luoh, M. C. (2008). <a href=\"https://www.jstor.org/stable/29730171\">Can hepatitis B mothers account for the number of missing women? Evidence from three million newborns in Taiwan</a>. <em>American Economic Review</em>, 98(5), 2259-73.{/ref}{ref}Monica Das Gupta, <a href=\"https://academic.oup.com/wbro/article-abstract/23/2/201/1662748\">Can Biological Factors Like Hepatitis B Explain the Bulk of Gender Imbalance in China? A Review of the Evidence</a>, <em>The World Bank Research Observer</em>, Volume 23, Issue 2, Fall 2008, Pages 201\u2013217.{/ref}</p>\n\n\n\n<p><b>Sex-selective abortions and discrimination against girls</b><br>After the hepatitis B hypothesis was debunked, no clear evidence of a biological factor in such skewed sex ratios has emerged. There is some variability in the <a href=\"https://ourworldindata.org/gender-ratio#definitions\">&#8220;expected&#8221; sex ratio</a> which may result from biological or environmental factors \u2013 a figure of 105 boys per 100 girls is usually adopted, but often this can vary from 103 to 107 boys per 100 girls. But the natural variability of the sex ratio is too small to explain the high ratios in some countries.</p>\n\n\n\n<p>The evidence for sex-selective abortion and discrimination against girls is now strong across several countries. Not only does the increase in sex ratios coincide with the availability of prenatal sex determination technologies, there is also clear evidence from studies investigating the use and promotion of such methods.</p>\n\n\n\n<p>In India, for example, prenatal diagnosis (PD) became available in the 1970s, shortly after legalization of medical abortion in 1971.{ref}Madan, K., &amp; Breuning, M. H. (2014). <a href=\"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4052431/\">Impact of prenatal technologies on the sex ratio in India: an overview</a>. <em>Genetics in Medicine</em>, 16(6), 425.{/ref} Whilst its use was intended for detection of abnormalities, it was soon used and promoted by the Indian medical profession for sex determination.{ref}Sharma, B. R., Gupta, N., &amp; Relhan, N. (2007). <a href=\"https://www.sciencedirect.com/science/article/pii/S0033350607000960\">Misuse of prenatal diagnostic technology for sex-selected abortions and its consequences in India</a>. <em>Public Health</em>, 121(11), 854-860.{/ref} Even after its use for sex determination was prohibited, studies suggest many gynecologists did not consider sex-selection abortion to be unethical and argued that it was an important intervention to balance population control with the desire for sons.{ref}Correspondent, L. I. (1983). <a href=\"https://www.ncbi.nlm.nih.gov/pubmed/11644254\">Misuse of amniocentesis</a>. <em>Lancet</em>, 321, 812-813.{/ref}</p>\n\n\n\n<p>Results from some of the earliest studies on abortions following the availability of prenatal sex determination are striking. Over the year from 1976 to 1977, at an urban hospital in India, 96% of the girls who were tested were aborted; in contrast, all of the 250 boys tested \u2013 including those with an identified risk of genetic defect \u2013 were born.{ref}Ramanamma, A., &amp; Bambawale, U. (1980). <a href=\"https://www.sciencedirect.com/science/article/pii/0160798780900599\">The mania for sons: an analysis of social values in South Asia</a>. <em>Social Science &amp; Medicine. Part B: Medical Anthropology</em>, 14(2), 107-110.{/ref} At a clinic in Mumbai, all of the 15,914 abortions after sex determination in 1984/85 were girls. Results from another six hospitals in the city found 7,999 of the 8,000 aborted fetuses in 1988 were girls.{ref}Tandon SL, Sharma R. (2006). <a href=\"http://www.sascv.org/ijcjs/previousissues.html\">Female foeticide and infanticide in India: an analysis of crimes against girl children</a>. <em>International Journal of Criminal Justice Science</em>.{/ref}</p>\n\n\n\n<p>The evidence that highly skewed sex ratios at birth have been largely the result of gender discrimination and selective abortions has been well-established across several countries. We discuss the reasons for this discrimination <a href=\"https://ourworldindata.org/gender-ratio#why-is-there-preference-for-a-son\"><strong>here</strong></a>.</p>\n\n\n\n<p>There are some additional hypotheses as to why the sex ratio at birth is skewed in some countries. Based on Chinese census data, Shi and Kennedy (2016) argue that the skew in China&#8217;s sex ratio is not the result of selective abortion practices, but much more the result of administrative anomalies.{ref}Shi, Y., &amp; Kennedy, J. J. (2016). <a href=\"https://www.cambridge.org/core/journals/china-quarterly/article/delayed-registration-and-identifying-the-missing-girls-in-china/0759987A48A37E3D2CFE157778747E33\">Delayed registration and identifying the \u201cmissing girls\u201d in China</a>.&nbsp;<em>The China Quarterly</em>,&nbsp;<em>228</em>, 1018-1038.{/ref} The authors argue that the one-child policy led some parents to postpone the registration of daughters (making them appear &#8220;missing&#8221;), but that they appear later in Chinese census data. A year later, Cai (2017) challenged the authors&#8217; conclusions in support of the conventional hypothesis that this is not a statistical artefact, but a real demographic&nbsp; and social challenge.{ref}Cai, Y. (2017). <a href=\"https://www.cambridge.org/core/journals/china-quarterly/article/missing-girls-or-hidden-girls-a-comment-on-shi-and-kennedys-delayed-registration-and-identifying-the-missing-girls-in-china/61E21855F8A1D958660973841BBC46FD\">Missing Girls or Hidden Girls? A Comment on Shi and Kennedy&#8217;s \u201cDelayed Registration and Identifying the \u2018Missing Girls\u2019 in China\u201d</a>.&nbsp;<em>The China Quarterly</em>,&nbsp;<em>231</em>, 797-803.{/ref}</p>\n\n\n\n<h3>Infanticide</h3>\n\n\n\n<p>Sex discrimination can occur prenatally (in the form of sex-selective abortions, as we discuss <a href=\"https://ourworldindata.org/gender-ratio#biology-or-discrimination-which-countries-have-skewed-sex-ratios-at-birth\"><strong>here</strong></a>) or postnatally when it can lead to the death of a child in the very worst cases. The death of a child due to sex discrimination can be brought about in a deliberate killing of an infant (infanticide) or can be caused by neglect or poor and unequal treatment.</p>\n\n\n\n<p>Over time, prenatal discrimination has increased as both abortions and sex determination technologies have become more readily available. Nonetheless, postnatal discrimination still occurs and has a long history.</p>\n\n\n\n<h4><b>Infanticide has a long history</b></h4>\n\n\n\n<p>Infanticide (or infant homicide) \u2013 the deliberate killing of newborns and infants \u2013 has a long history.{ref}Moseley, K. L. (1985).<a href=\"https://heinonline.org/HOL/LandingPage?handle=hein.journals/ilmed1&amp;div=42&amp;id=&amp;page=\"> The history of infanticide in Western society</a>. <em>Issues in Law &amp; Medicine</em>, 1, 345.{/ref}{ref}Levittan, M. (2012). The history of infanticide: exposure, sacrifice, and femicide. <em>Violence and Abuse in Society. Understanding a Global Crisis</em>. Santa Barbara, ABC-CLIO, 83-130.{/ref}&nbsp;From hunter-gatherers to ancient civilizations to the present day: infanticide has spanned all periods of history. In fact, anthropologist Laila Williamson goes as far to say: \u201cInfanticide has been practiced on every continent and by people on every level of cultural complexity, from hunter gatherers to high civilizations, including our own ancestors. Rather than being an exception, then, it has been the rule.&#8221;{ref}Williamson, Laila (1978). &#8220;Infanticide: an anthropological analysis&#8221;. In Kohl, Marvin (ed.). <em>Infanticide and the Value of Life</em>. NY: <a href=\"https://en.wikipedia.org/wiki/Prometheus_Books\">Prometheus Books</a>. pp. 61\u201375.{/ref}</p>\n\n\n\n<p><span style=\"font-weight: 400;\">And humans are not alone. From birds to rodents; fish to mammals; we find evidence of infanticide across the animal kingdom.</span>{ref}Hausfater, G., &amp; Hrdy, S. B. (2017). <em>Infanticide: comparative and evolutionary perspectives</em>. Routledge.{/ref}</p>\n\n\n\n<p><span style=\"font-weight: 400;\">There are some common misconceptions today surrounding the practice of infanticide. Although the term is now often adopted as a synonym for \u2018female infanticide\u2019 \u2013 the killing of unwanted girls \u2013 the gender specifics and drivers of infanticide depend on context and time in history.</span>{ref}Scott, E. (2017, June). <a href=\"https://books.google.co.uk/books?hl=en&amp;lr=&amp;id=n98jDwAAQBAJ&amp;oi=fnd&amp;pg=PA143&amp;dq=unpicking+a+myth:+the+infanticide&amp;ots=2XS6lFMoJO&amp;sig=AdzrpXxZR3RWGNd-qf0FducA81I#v=onepage&amp;q=unpicking%20a%20myth%3A%20the%20infanticide&amp;f=false\">Unpicking a myth: the infanticide of female and disabled infants in antiquity</a>. In <em>TRAC 2000: Proceedings of the Tenth Annual Theoretical Archaeology Conference. London 2000</em> (p. 143). Oxbow Books.{/ref}</p>\n\n\n\n<h4><b>Historical evidence and estimates of infanticide</b></h4>\n\n\n\n<p><b><span style=\"font-weight: 400;\">A number of researchers have studied the demographic, health and cultural profiles of prehistoric societies. In rare cases they can use indirect evidence of the fossil record; but many rely on modern hunter-gatherer societies today.{ref}This of course introduces uncertainty as to how good an analogue modern hunter-gatherers are to prehistoric societies. Modern hunter-gatherer societies may have some contact and transfer with external influence. As a result, researchers often focus on societies with as little external influence as possible, for example having no nutritional, health, sanitation or technology transfer.{/ref}</span></b></p>\n\n\n\n<p><span style=\"font-weight: 400;\">Estimates for infanticide in prehistoric societies are very high. Using recent hunter-gatherer societies as a proxy, some studies suggest anywhere from 15% to 50% of newborns were killed in the first year of life.</span>{ref}Birdsell, Joseph, B. (1986). &#8220;Some predictions for the Pleistocene based on equilibrium systems among recent hunter gatherers&#8221;. In Lee, Richard &amp; Irven DeVore (ed.). <em>Man the Hunter</em>. Aldine Publishing Co. p. 239.{/ref}&nbsp;Other estimates are lower, but still very high: in the range of 15-20%.{ref}Williamson, Laila (1978). &#8220;Infanticide: an anthropological analysis&#8221;. In Kohl, Marvin (ed.). <em>Infanticide and the Value of Life</em>. NY: <a href=\"https://en.wikipedia.org/wiki/Prometheus_Books\">Prometheus Books</a>. pp. 61\u201375.{/ref}<span style=\"font-weight: 400;\"> </span></p>\n\n\n\n<p><span style=\"font-weight: 400;\">Hill &amp; Walker (2007) looked at the demographic profiles, death rates and causes of death of recent hunter-gatherers: the Hiwi group of Venezuela. They did this using census and interviews gathered over a seven year period.</span>{ref}Hill, K., Hurtado, A. M., &amp; Walker, R. S. (2007). <a href=\"https://www.sciencedirect.com/science/article/pii/S0047248406002193\">High adult mortality among Hiwi hunter-gatherers: Implications for human evolution</a>. <em>Journal of Human Evolution</em>, <em>52</em>(4), 443-454.{/ref}&nbsp;They found very high rates of infant death from violence. Infant mortality rates in the past were very high \u2013 most studies suggest around a quarter of newborns did not survive the first year of life.&nbsp;<span style=\"font-weight: 400;\">In the Hiwi hunter-gatherers, researchers found homicide to be the second largest cause of death, accounting for 30%. They also found large sex differences: infanticide rates were four times higher for girls than boys.</span></p>\n\n\n\n<p><span style=\"font-weight: 400;\">Other studies of modern hunter-gatherer societies analysed the sex ratio of infants to estimate the prevalence of infanticide. Very skewed sex ratio of infants is suggestive of select infanticide. In studying 86 hunter-gatherer bands across North America, South America, Africa, Asia and Australia, researchers found high levels of female infanticide across 77 of them.</span>{ref}Divale, W. T. (1972). <a href=\"https://www.tandfonline.com/doi/abs/10.1080/00438243.1972.9979534\">Systemic population control in the middle and upper palaeolithic: Inferences based on contemporary hunter\u2010gatherers</a>. <em>World Archaeology</em>, <em>4</em>(2), 222-243.{/ref}</p>\n\n\n\n<p><span style=\"font-weight: 400;\">This is shown in the table, where there were many more young males than females in bands where infanticide was reported as \u2018common\u2019 or \u2018occasional\u2019.</span></p>\n\n\n\n<table id=\"tablepress-111\" class=\"tablepress tablepress-id-111\">\n<thead>\n<tr class=\"row-1 odd\">\n\t<th class=\"column-1\">Infanticide reported as:</th><th class=\"column-2\">Youth sex ratio <br>(males per 100 females)</th><th class=\"column-3\">Adult sex ratio <br>(males per 100 females)</th><th class=\"column-4\">Number of hunter-gathering bands</th>\n</tr>\n</thead>\n<tbody class=\"row-hover\">\n<tr class=\"row-2 even\">\n\t<td class=\"column-1\">Common</td><td class=\"column-2\">138</td><td class=\"column-3\">105</td><td class=\"column-4\">71</td>\n</tr>\n<tr class=\"row-3 odd\">\n\t<td class=\"column-1\">Occasional</td><td class=\"column-2\">138</td><td class=\"column-3\">80</td><td class=\"column-4\">6</td>\n</tr>\n<tr class=\"row-4 even\">\n\t<td class=\"column-1\">Not common</td><td class=\"column-2\">100</td><td class=\"column-3\">85</td><td class=\"column-4\">3</td>\n</tr>\n<tr class=\"row-5 odd\">\n\t<td class=\"column-1\">Not practised</td><td class=\"column-2\">94</td><td class=\"column-3\">83</td><td class=\"column-4\">6</td>\n</tr>\n</tbody>\n</table>\n\n\n\n\n<p><span style=\"font-weight: 400;\">The practice of infanticide was not just common in prehistoric societies, but was also very common in many \u2013 but not all \u2013 ancient cultures.</span>{ref}Langer, W. L. (1974). <a href=\"https://search.proquest.com/docview/1305583868\">Infanticide: A historical survey</a>. <em>The Journal of Psychohistory</em>, <em>1</em>(3), 353.{/ref}&nbsp;Evidence for this exists either in the form of preserved burial remains, documented records or writings suggestive of the practice.{ref}Milner, Larry S. (2000). <em>Hardness of Heart / Hardness of Life: The Stain of Human Infanticide</em>. Lanham/New York/Oxford: University Press of America.{/ref}</p>\n\n\n\n<h4><b>Both sexes</b> are victims of infanticide</h4>\n\n\n\n<p><span style=\"font-weight: 400;\">It\u2019s a common assumption that infanticide relates only to female infanticide: the killing of unwanted girls.</span>{ref}Scott, E. (2017, June). <a href=\"https://books.google.co.uk/books?hl=en&amp;lr=&amp;id=n98jDwAAQBAJ&amp;oi=fnd&amp;pg=PA143&amp;dq=unpicking+a+myth:+the+infanticide&amp;ots=2XS6lFMoJO&amp;sig=AdzrpXxZR3RWGNd-qf0FducA81I#v=onepage&amp;q=unpicking%20a%20myth%3A%20the%20infanticide&amp;f=false\">Unpicking a myth: the infanticide of female and disabled infants in antiquity</a>. In <em>TRAC 2000: Proceedings of the Tenth Annual Theoretical Archaeology Conference. London 2000</em> (p. 143). Oxbow Books.{/ref}&nbsp;But the role or direction of gender discrimination \u2013 either towards boys or girls \u2013 is context-dependent.{ref}Hughes, A. L. (1981). <a href=\"https://www.sciencedirect.com/science/article/pii/0162309581900236\">Female infanticide: Sex ratio manipulation in humans</a>. <em>Ethology and Sociobiology</em>, 2(3), 109-111.{/ref}</p>\n\n\n\n<p><span style=\"font-weight: 400;\">Sometimes here is no clear gender discrimination, and it occurs for both sexes.</span></p>\n\n\n\n<p><span style=\"font-weight: 400;\">There is of course significant evidence of female-selective infanticide throughout history: we see that in the sex ratio of many hunter-gatherer societies above through to skewed ratios in Medieval England.</span>{ref}Kellum, B. A. (1974). <a href=\"https://search.proquest.com/openview/c1ae81634e9d46b2e7402da67bc5eeef/1?pq-origsite=gscholar&amp;cbl=1816657\">Infanticide in England in the later Middle Ages</a>. <em>The Journal of Psychohistory</em>, <em>1</em>(3), 367.{/ref}&nbsp;Evidence of male-selective infanticide is rarer, but does exist: in a sample of 93 preindustrial culture, 9 showed evidence of female-selective, while 1 showed male-selective infanticide.{ref}Hughes, A. L. (1981). <a href=\"https://www.sciencedirect.com/science/article/pii/0162309581900236\">Female infanticide: Sex ratio manipulation in humans</a>. <em>Ethology and Sociobiology</em>, 2(3), 109-111.{/ref}</p>\n\n\n\n<p><span style=\"font-weight: 400;\">Even today, cases on infanticide still exist, despite being outlawed in most countries.</span>{ref}Cecilia Lai\u2010wan, C., Eric, B., &amp; Celia Hoi\u2010yan, C. (2006).<a href=\"https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=Cecilia+Lai%E2%80%90wan%2C+C.%2C+Eric%2C+B.%2C+%26+Celia+Hoi%E2%80%90yan%2C+C.+%282006%29.+Attitudes+to+and+practices+regarding+sex+selection+in+China.+Prenatal+Diagnosis%3A+Published+in+Affiliation+With+the+International+Society+for+Prenatal+Diagnosis%2C+26%287%29%2C+610-613.&amp;btnG=\"> Attitudes to and practices regarding sex selection in China</a>. <em>Prenatal Diagnosis: Published in Affiliation With the International Society for Prenatal Diagnosis</em>, 26(7), 610-613.{/ref} Infanticide occurs in Western countries: in some (such as the United States) boys make up a higher share of infant homicides.{ref}Porter, T., &amp; Gavin, H. (2010). <a href=\"https://journals.sagepub.com/doi/abs/10.1177/1524838010371950\">Infanticide and neonaticide: a review of 40 years of research literature on incidence and causes</a>. <em>Trauma, Violence, &amp; Abuse</em>, <em>11</em>(3), 99-112.{/ref}&nbsp;But the most widely prevalent \u2013 and selection that has a significant impact on gender ratio \u2013 is female infanticide. This remains reported across countries with a strong son preference: India and China are the most documented examples.{ref}Chunkath, S. R., &amp; Athreya, V. B. (1997). <a href=\"https://www.jstor.org/stable/4405340\">Female infanticide in Tamil Nadu: some evidence</a>. <em>Economic and political weekly</em>, WS21-WS28.{/ref}{ref}Lee, B. J. (1981). <a href=\"https://www.jstor.org/stable/41298766\">Female infanticide in China</a>. <em>Historical Reflections/R\u00e9flexions Historiques</em>, 163-177.{/ref}</p>\n\n\n\n<p><span style=\"font-weight: 400;\">Infanticide is the most direct case of postnatal sex selection. More often overlooked is the excess mortality which results from neglect and unequal treatment of girls. This is \u2018excess female mortality\u2019 is sometimes often referred to as \u2018delayed infanticide\u2019.</span></p>\n\n\n\n<h3>Excess female mortality</h3>\n\n\n\n<p><b>Poor treatment of girls results in increased mortality in childhood</b><br>In almost every country young boys are more likely to die in childhood than girls \u2013 as we explore <a href=\"https://ourworldindata.org/gender-ratio#why-do-boys-die-more-often-than-girls\"><strong>here</strong></a>, there are several biological reasons for is. But this is not true in a few counties \u2013 India is one notable example today. There, girls die more often than boys.</p>\n\n\n\n<p>When we compare infant (under one year old) and child (under-5s) mortality rates between boys and girls in India we see that the difference is bigger for the older age group. While infant mortality rates are approximately the same, the child mortality rate for girls is higher.</p>\n\n\n\n<p>Let&#8217;s then focus on children rather than infants. In the chart here we see mortality rates for boys (on the y-axis) and girls (on the x-axis) for various causes in India. This data is shown for children aged 1-4 years old in 2017. Here we see that for many, death rates are significantly higher for girls. Some of these \u2013 hepatitis, measles or tuberculosis, for example \u2013 we expect to be higher for girls. But not for infections, respiratory and diarrheal diseases. Note also the much higher mortality rates for nutritional deficiencies and protein-energy malnutrition for girls.</p>\n\n\n\n<iframe style=\"width: 100%; height: 600px; border: 0px none;\" src=\"https://ourworldindata.org/grapher/child-deaths-by-cause-by-sex-india\"></iframe>\n\n\n\n<p>Poorer health outcomes for girls across some countries \u2013 often in Asia and not restricted to India \u2013 has been well-documented.{ref}Million Death Study Collaborators. (2010). <a href=\"https://www.sciencedirect.com/science/article/pii/S0140673610614614\">Causes of neonatal and child mortality in India: a nationally representative mortality survey</a>. <em>The Lancet</em>, 376(9755), 1853-1860.{/ref}{ref}Raj, A., McDougal, L. P., &amp; Silverman, J. G. (2015). <a href=\"https://link.springer.com/article/10.1007/s10995-014-1513-0\">Gendered effects of siblings on child malnutrition in South Asia: cross-sectional analysis of demographic and health surveys from Bangladesh, India, and Nepal</a>. <em>Maternal and Child Health Journal</em>, 19(1), 217-226.{/ref} Even for some countries where the child mortality rate remains higher in boys than for the girls, death rates for girls are still higher than would be expected.</p>\n\n\n\n<p>Social preference for a boy has resulted in unequal treatment of young girls in a number of ways. Studies have shown in some countries:</p>\n\n\n\n<ul><li>poorer nutrition for girls and unequal food distribution;{ref}Aurino, E. (2017). <a href=\"https://www.sciencedirect.com/science/article/pii/S1570677X16301666\">Do boys eat better than girls in India? Longitudinal evidence on dietary diversity and food consumption disparities among children and adolescents</a>. <em>Economics &amp; Human Biology</em>, 25, 99-111.{/ref}</li><li>less breastfeeding from mothers for daughters than for sons;{ref}Jayachandran, S., &amp; Kuziemko, I. (2011). <a href=\"https://academic.oup.com/qje/article-abstract/126/3/1485/1854553\">Why do mothers breastfeed girls less than boys? Evidence and implications for child health in India</a>. <em>The Quarterly Journal of Economics</em>, 126(3), 1485-1538.{/ref}</li><li>lower healthcare utilization for girls;{ref}Ghosh, N., Chakrabarti, I., Chakraborty, M., &amp; Biswas, R. (2013). <a href=\"https://www.ijmedph.org/article/60?qt-sidebar_tabs=2\">Factors affecting the healthcare-seeking behavior of mothers regarding their children in a rural community of Darjeeling district, West Bengal</a>. <em>International Journal of Medicine and Public Health</em>, 3(1).{/ref}{ref}Barcellos, S. H., Carvalho, L. S., &amp; Lleras-Muney, A. (2014). <a href=\"https://www.aeaweb.org/articles?id=10.1257/app.6.1.157\">Child gender and parental investments in India: Are boys and girls treated differently?</a>. <em>American Economic Journal: Applied Economics</em>, 6(1), 157-89.{/ref}</li><li>during pregnancy there is evidence of preferential treatment for boys with more antenatal visits and increased tetanus vaccinations.{ref}Bharadwaj, P., &amp; Lakdawala, L. K. (2013). <a href=\"https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=Bharadwaj%2C+P.%2C+%26+Lakdawala%2C+L.+K.+%282013%29.+Discrimination+begins+in+the+womb%3A+Evidence+of+sex-selective+prenatal+investments.+Journal+of+Human+Resources%2C+48%281%29%2C+71-113.&amp;btnG=\">Discrimination begins in the womb: Evidence of sex-selective prenatal investments</a>. <em>Journal of Human Resources</em>, 48(1), 71-113.{/ref}</li></ul>\n\n\n\n<p>This combination of poorer nutrition and healthcare investment can result in higher mortality rates for girls, but also to excess mortality for women in later stages of life.</p>\n\n\n\n<h3>How many women are missing?</h3>\n\n\n\n<p>The term &#8216;missing women&#8217; was first coined by Indian economist Amartya Sen in a 1990 article; he estimated &#8220;more than 100 million women are missing&#8221;.{ref}Sen, A. (1990). <a href=\"http://www.ouazad.com/nyustats/resources/reading-week1.pdf\">More than 100 million women are missing</a>. <em>The New York Review of Books</em>, 37(20), 61-66.{/ref}</p>\n\n\n\n<p>&#8216;Missing women&#8217; refers to the shortfall of women from the number we would expect in the absence of sex discrimination. It is the sum of women who are missing at birth (as a result of sex-selective prenatal practices such as abortion) and excess female mortality later in life (either through infanticide, child neglect or maltreatment).</p>\n\n\n\n<p>Many researchers have tried to calculate the number of missing women. Using sex ratios at birth, and at different ages we can compare the observed and expected values: the difference is then defined as girls and women who are missing.</p>\n\n\n\n<p>There are very obvious challenges in calculating this figure. For the observed sex ratio, there is the concern of how accurate the reported number of births, males and females are. The other major issue is knowing exactly what the baseline/expected ratio of males to females would be at each stage in life. For example, the <a href=\"https://ourworldindata.org/gender-ratio#definitions\">&#8216;expected&#8217; sex ratio at birth</a> is quoted as 105 male births per 100 female births. But through time and across the world, this can often vary between 103 to 107 male births per 100 female births. The combination of these measurement issues means any estimate of the number of missing women will come with fairly high uncertainty.</p>\n\n\n\n<p>In the table here we provide a summary of a range of estimates \u2013 note here that the year of the estimate is different for each.<b> </b>Here we see that although there is significant uncertainty in these estimates, all are within the range of over 50 million by 1990, and likely upwards of 100 million today.</p>\n\n\n\n<p>In the chart we see some of the most recent estimates of missing women from 1970 through to 2015 from Bongaarts &amp; Guilmoto (2015).{ref}Bongaarts, J., &amp; Guilmoto, C. Z. (2015). <a href=\"https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=doi.org%2F10.1111%2Fj.1728-4457.2015.00046.x&amp;btnG=\">How many more missing women? Excess female mortality and prenatal sex selection, 1970\u20132050</a>. <em>Population and Development Review</em>, 41(2), 241-269.{/ref} In 1970 the researchers estimated there were 61 million missing women; by 2015, 136 million. This is more than the <a rel=\"noopener noreferrer nofollow\" data-token-index=\"1\" data-reactroot=\"\" href=\"https://ourworldindata.org/grapher/population-by-country-gapminder+un?tab=chart&amp;time=1800..2019&amp;country=MEX\" target=\"_blank\">population of Mexico</a>. We see that more than 80% are missing from China and India \u2013 68 and 45 million, respectively.</p>\n\n\n\n<p>The authors also provided projections of the number of missing women through demographic changes to 2050 which you <a href=\"https://ourworldindata.org/grapher/global-number-of-missing-women\"><strong>find here</strong></a>.</p>\n\n\n\n<table id=\"tablepress-106\" class=\"tablepress tablepress-id-106\">\n<thead>\n<tr class=\"row-1 odd\">\n\t<th class=\"column-1\">Source</th><th class=\"column-2\">Year estimate is for</th><th class=\"column-3\">Number of missing women</th>\n</tr>\n</thead>\n<tbody class=\"row-hover\">\n<tr class=\"row-2 even\">\n\t<td class=\"column-1\">Sen (1990, 1992)</td><td class=\"column-2\">1990</td><td class=\"column-3\">More than 100 million</td>\n</tr>\n<tr class=\"row-3 odd\">\n\t<td class=\"column-1\">Coale (1991)</td><td class=\"column-2\">1990</td><td class=\"column-3\">60 million</td>\n</tr>\n<tr class=\"row-4 even\">\n\t<td class=\"column-1\">Klasen (1994)</td><td class=\"column-2\">1990</td><td class=\"column-3\">92 million</td>\n</tr>\n<tr class=\"row-5 odd\">\n\t<td class=\"column-1\">Klasen and Wink (2002)</td><td class=\"column-2\">1990s</td><td class=\"column-3\">102 million</td>\n</tr>\n<tr class=\"row-6 even\">\n\t<td class=\"column-1\">Hudson &amp; Den Boer (2004)</td><td class=\"column-2\">2000s</td><td class=\"column-3\">90 million</td>\n</tr>\n<tr class=\"row-7 odd\">\n\t<td class=\"column-1\">Guilmoto (2012)</td><td class=\"column-2\">2010</td><td class=\"column-3\">117 million</td>\n</tr>\n<tr class=\"row-8 even\">\n\t<td class=\"column-1\">Bongaarts &amp; Guilmoto (2015)</td><td class=\"column-2\">2015</td><td class=\"column-3\">136 million</td>\n</tr>\n</tbody>\n</table>\n\n\n\n\n<iframe src=\"https://ourworldindata.org/grapher/global-number-of-missing-women?time=earliest..2015\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h4>How many girls and women are missing every year?</h4>\n\n\n\n<p>Above are estimates of the total number of missing women in the world. But how many are &#8216;missing&#8217; each year?</p>\n\n\n\n<p>In this chart we see estimates of (1) the number of &#8216;missing&#8217; female births from prenatal sex discrimination; and (2) excess female deaths as a result of postnatal discrimination.{ref}Bongaarts, J., &amp; Guilmoto, C. Z. (2015). <a rel=\"noreferrer noopener\" href=\"https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=doi.org%2F10.1111%2Fj.1728-4457.2015.00046.x&amp;btnG=\" target=\"_blank\">How many more missing women? Excess female mortality and prenatal sex selection, 1970\u20132050</a>. Population and Development Review, 41(2), 241-269.{/ref}</p>\n\n\n\n<p>3.3 million women is the estimate fo 2015 \u2013 approximately half of which were missing births and half of which are attributed to excess female mortality. After the 1970s sex-selective abortions (shown as missing births) became more common. Until 1980, nearly all missing women were the result of excess female mortality; by 2015 as many were from missing births each year.</p>\n\n\n\n<iframe style=\"width: 100%; height: 600px; border: 0px none;\" src=\"https://ourworldindata.org/grapher/missing-female-births-and-excess-mortality\"></iframe>\n\n\n\n<h2>Why is there a preference for a son in some places?</h2>\n\n\n\n<p>In countries where there is a clear imbalance in sex ratio, there&#8217;s preference for a boy. But why does this preference exist?</p>\n\n\n\n<p>Son preference is most common in countries across East and South Asia, but also in some countries in the Middle East and North Africa.{ref}Hesketh, T., Lu, L., &amp; Xing, Z. W. (2011). <a href=\"http://www.cmaj.ca/content/183/12/1374\">The consequences of son preference and sex-selective abortion in China and other Asian countries</a>. <em>CMAJ</em>, 183(12), 1374-1377.{/ref} Although there are significant cultural, economic and societal differences between these countries there are important parallels which explain strong preference for a boy.</p>\n\n\n\n<p>What these countries tend to have in common is a strong logic of &#8216;patrilineality&#8217;: the logic that productive assets move through the male line within the family.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., &amp; Hwa-Ok, B. (2003). <a href=\"https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=doi.org%2F10.1080%2F00220380412331293807&amp;btnG=\">Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea</a>. <em>The Journal of Development Studies</em>, 40(2), 153-187.{/ref} Although many other countries also have patrilineality to some degree, in countries with a strong preference for a son, researchers find this logic to be much more rigid. The social order of families resides with the males: lineage is passed from father to son. Men within the social order are the fixed points, and women the moving points: when a daughter marries, she leaves the current family to join a new one.</p>\n\n\n\n<p>This can produce&nbsp;economic and social benefits to having a son rather than a daughter, including:</p>\n\n\n\n<ul><li><strong><em>Family name</em></strong>: the lineage within a family stays within the male line. Having a son therefore continues the family name.</li><li><strong><em>Old age support</em></strong>: sons within a family are often responsible for supporting parents in illness and old age.{ref}Hesketh, T., Lu, L., &amp; Xing, Z. W. (2011). <a href=\"http://www.cmaj.ca/content/183/12/1374\">The consequences of son preference and sex-selective abortion in China and other Asian countries</a>. <em>CMAJ</em>, 183(12), 1374-1377.{/ref} Elderly parents often live with married children and overwhelmingly so with their sons. This provides a strong economic incentive for a son for old age support. It&#8217;s a key differentiating factor between countries with and without strong son preference: in Taiwan, it&#8217;s rare for parents to live with a married daughter, but in the Philippines (without strong son preference) parents are equally likely to live with the son or daughter.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., &amp; Hwa-Ok, B. (2003). <a href=\"https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=doi.org%2F10.1080%2F00220380412331293807&amp;btnG=\">Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea</a>. <em>The Journal of Development Studies</em>, 40(2), 153-187.{/ref}</li><li><strong><em>Dowries</em></strong>: a dowry \u2013 the transfer of property or money from the bride&#8217;s to the groom&#8217;s family \u2013 is an important economic concern for having a daughter. Studies in India have suggested that a dowry is the most common reason for not wanting a girl.{ref}Diamond\u2010Smith, N., Luke, N., &amp; McGarvey, S. (2008). <a href=\"https://www.tandfonline.com/doi/full/10.1080/13691050802061665\">\u2018Too many girls, too much dowry\u2019: son preference and daughter aversion in rural Tamil Nadu, India</a>. <em>Culture, Health &amp; Sexuality</em>, 10(7), 697-708.{/ref} Even when parents themselves didn&#8217;t have a dowry in their own marriage, many carry the expectation of having to provide one for a daughter, or asking for one from a future daughter-in-law. </li><li><strong><em>Labor force opportunities</em></strong>: males can bring better economic opportunities for a family. This can be the result of real sex differences in economic opportunities, but also results from undervaluing the work of women. In many countries, unpaid or informal work <a href=\"https://ourworldindata.org/female-labor-supply#informal-work-unpaid-care-work\">accounts for a majority share</a> of female employment. In this sense, informal employment is often seen simply as an extension of a women&#8217;s domestic work rather than being valued in its own right.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., &amp; Hwa-Ok, B. (2003). <a href=\"https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=doi.org%2F10.1080%2F00220380412331293807&amp;btnG=\">Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea</a>. <em>The Journal of Development Studies</em>, 40(2), 153-187.{/ref}</li><li><strong><em>Family and societal pressure</em></strong>: it&#8217;s not just economic concerns that parents worry about: surveys also reveal persistent pressures from family members and communities. In interviews, women often note pressures from female in-laws and husbands, verbal and physical abuse when they didn&#8217;t produce a son or were pregnant with a girl.{ref}Puri, S., Adams, V., Ivey, S., &amp; Nachtigall, R. D. (2011). <a href=\"https://www.sciencedirect.com/science/article/pii/S0277953611000700\">\u201cThere is such a thing as too many daughters, but not too many sons\u201d: A qualitative study of son preference and fetal sex selection among Indian immigrants in the United States</a>. <em>Social Science &amp; Medicine</em>, 72(7), 1169-1176.{/ref}</li><li><strong><em>Religion</em></strong>: in some cultures it&#8217;s believed that only a son can light the funeral pyre and carry out death-related rites and rituals needed for salvation.{ref}Tandon, S. L., &amp; Sharma, R. (2006). <a href=\"https://www.sascv.org/ijcjs/snehlata.pdf\">Female Foeticide and Infanticide in India: An Analysis of Crimes against Girl Children</a>. <em>International Journal of Criminal Justice Sciences</em>, 1(1).{/ref}</li></ul>\n\n\n\n<h2>What are the consequences of a skewed sex ratio?</h2>\n\n\n\n<p>Across several countries in Asia, and North Africa we see highly skewed sex ratios in favour of males. Strong preference for sons has led to an increasing number of &#8220;missing women&#8221; and therefore an &#8220;excess of males&#8221;.</p>\n\n\n\n<p>There are a number of adverse consequences which could result from highly imbalanced numbers of men and women in society. These present a risk to men, women, family structures and society as a whole.</p>\n\n\n\n<p>The obvious consequence of gender imbalance is a large number of unmarriageable men.{ref}Hesketh, T. (2011). <a href=\"https://www.sciencedirect.com/science/article/pii/S0378378211002763\">Selecting sex: The effect of preferring sons</a>. <em>Early Human Development</em>, 87(11), 759-761.{/ref} A lack of women of marriageable age could have several impacts on marriage dynamics for men:{ref}Guilmoto, C. Z. (2007). <a href=\"https://pdfs.semanticscholar.org/b1e7/3587d7bce7cec908286fba3f3c0b32257566.pdf\">Sex-ratio imbalance in Asia: Trends, consequences and policy responses</a>. <em>Paris: LPED/IRD</em>.{/ref}</p>\n\n\n\n<ul><li>many men will have to delay marriage;</li><li>this will have a knock-on impact on younger men: not only will they be impacted by a skewed sex ratio for their generation, but will also have a &#8216;backlog&#8217; of men from the previous generation in the &#8216;marriage market&#8217;;</li><li>a significant number of men will have to forego marriage altogether;</li><li>the poorest men will likely be most highly impacted by this \u2013 it&#8217;s hypothesised that women will &#8220;marry up&#8221; in society, leaving the men with least resources disproportionately affected;</li><li>one of the most common reasons for son preference is for family lineage (the passing down of the family name through males in the family) \u2013 this will likely not occur in families where sons do not marry.</li></ul>\n\n\n\n<p>Whilst we might assume that this dynamic would favour women, they could also suffer negative consequences:</p>\n\n\n\n<ul><li>a women&#8217;s value may be increasingly lie in her role as a wife, daughter-in-law or mother. This may deny her alternative pathways, such as remaining single or becoming more career-oriented;</li><li>women may feel increased pressure or incentives to marry or have children earlier in life (possibly closing off different economic or labour opportunities);</li><li>women may be at increased risk of violence (emotional, sexual or physical) or trafficking.{ref}Hudson, V. M., &amp; Den Boer, A. (2005). <a href=\"https://kar.kent.ac.uk/11409/1/WW-missingwomen-05.pdf\">Missing women and bare branches: gender balance and conflict</a>. <em>Environmental Change and Security Program Report</em>, (11), 20-24.{/ref}</li></ul>\n\n\n\n<p>Imbalanced gender ratios could have negative consequences for both men and women. For society more broadly, there are several hypotheses that it will also result in more crime, violence and disorder in communities. The rationale being that not only will there be an excess of men who do not marry and have their own family, but that the most affected will be those of lowest socioeconomic status, the most uneducated and with fewer opportunities.</p>\n\n\n\n<p>Hudson and De Boer (2004) propose that this situation will result in significant social stability and security concerns.{ref}Hudson, V. M., &amp; Den Boer, A. (2005). <a href=\"https://kar.kent.ac.uk/11409/1/WW-missingwomen-05.pdf\">Missing women and bare branches: gender balance and conflict</a>. <em>Environmental Change and Security Program Report</em>, (11), 20-24.{/ref} Although studies have found correlation between the prevalence of violence and more imbalanced gender ratios, it&#8217;s difficult to disentangle a causal effect.{ref}Diamond-Smith, N., &amp; Rudolph, K. (2018). <a href=\"https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0197516\">The association between uneven sex ratios and violence: Evidence from 6 Asian countries</a>. <em>PLoS One</em>, 13(6), e0197516.{/ref} Other researchers suggest that the evidence does not support this concern: that rather than showing through aggression and violence, excluded men will be more marginalised, lonely and at risk of psychological problems.{ref}Hesketh, T. (2011). <a href=\"https://www.sciencedirect.com/science/article/pii/S0378378211002763\">Selecting sex: The effect of preferring sons</a>. <em>Early Human Development</em>, 87(11), 759-761.{/ref} What&#8217;s clear is that the persistence of imbalanced sex ratios means there will be demographic consequences for many decades to come.</p>\n\n\n\n<h2>What affects the strength of gender bias?</h2>\n\n\n\n<h3>Are richer and more educated parents less likely to have gender preference?</h3>\n\n\n\n<p>If our aim is to address the issue of a skewed sex ratio and female discrimination, an obvious question to ask is: will development fix the problem? Is it the case that son preference is restricted to those at lower incomes, therefore the problem disappear if <a href=\"https://owid.cloud/extreme-poverty\">poverty</a> falls and societies develop?</p>\n\n\n\n<p>The evidence to date suggests, no: development on its own does not address it.</p>\n\n\n\n<p>Studies which have looked in detail at the extent of sex ratio imbalances by demographic (comparing income level, education, literacy, employment factors amongst others) often conclude the opposite: that richer, urban families tend to discriminate more than the poor.{ref}Filmer, D., Friedman, J., &amp; Schady, N. (2008). <a href=\"https://elibrary.worldbank.org/doi/abs/10.1596/1813-9450-4716\">Development, modernization, and son preference in fertility decisions</a>. <em>The World Bank</em>.{/ref} For example, in North India higher castes (who tend to be richer) had more skewed sex ratios than lower castes.{ref}Gupta, M. D. (1987). <a href=\"https://www.jstor.org/stable/1972121\">Selective discrimination against female children in rural Punjab, India</a>. <em>Population and Development Review</em>, 13(1), 77-100.{/ref} Narrowing in on specific districts and household in India and South Korea suggested that it is richer families who show greater discrimination.{ref}Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., &amp; Hwa-Ok, B. (2003). <a href=\"https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C5&amp;q=doi.org%2F10.1080%2F00220380412331293807&amp;btnG=\">Why is son preference so persistent in East and South Asia? A cross-country study of China, India and the Republic of Korea</a>. <em>The Journal of Development Studies</em>, 40(2), 153-187.{/ref}</p>\n\n\n\n<p>Despite rising incomes and development across many countries in Asia, North Africa and Eastern Europe, the sex ratio got worse, not better. An important driver which may link the increase in sex ratio with development and rising incomes is fertility rates. As we show in our entry on <a href=\"https://owid.cloud/fertility-rate\">fertility rates</a>, there is a very strong impact of improving development and falling fertility. And falling fertility rates in turn play a key role in exacerbating gender preference. This is often called the &#8216;fertility squeeze&#8217;.</p>\n\n\n\n<p><strong>In smaller families, you&#8217;re less likely to have a son by chance</strong></p>\n\n\n\n<p>Imagine you have five or six children: there&#8217;s a very high chance that at least one of them will be a boy. For five children, there&#8217;s around a 98% chance you&#8217;ll have a son.{ref}To calculate this, we need to calculate the probability that in having 5 children, we have five girls. Because the &#8216;natural&#8217; sex ratio at birth is around 105 boys per 100 girls, the probability of having a girl at each birth is slightly lower than half: it&#8217;s around 47.6%. To calculate the probability of having 5 girls, we then do 0.476^5 = 0.0245 [or 2.45%]. The probability that you have at least one boy is therefore 100% &#8211; 2.45% = 97.6%.{/ref} Now imagine you have only one or two children: the likelihood you have a son is much smaller. If you have only one child, you&#8217;re chances of having a son are just over half (52%); if you have two children, the odds are 77%.{ref}Since the &#8216;natural&#8217; sex ratio at birth is around 105 boys per 100 girls, the odds of having a boy are slightly higher than having a girl: 52%. To calculate the odds of having a boy when you have two children, we start by calculating the probability of having two girls. The probability of having a girl at each birth is 47.6% [100/105 * 100]. The probability of two births producing two girls is then calculated as 0.476^2 = 0.227 [22.7%]. The odds that one is a boy is therefore 100% &#8211; 22.7% = 77%.{/ref}</p>\n\n\n\n<p>In many countries across the world, this <a href=\"https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=CHN+IND+KOR\">transition happened</a>: in India, average fertility rates <a href=\"https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=IND\">fell from almost 6 to 2 children per woman</a>; in China from over <a href=\"https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=CHN\">6 down to 1.2 children</a>; in South Korea from over <a href=\"https://ourworldindata.org/grapher/children-per-woman-un?tab=chart&amp;time=1950..2015&amp;country=KOR\">6 to just under one child per woman</a>. As countries got richer; education levels increased; women gained more rights to education labour participation and healthcare decisions; fertility rates fell rapidly.</p>\n\n\n\n<p>But the result is that if you really want a son, your chances of having one naturally are now much lower. For parents of fewer children with a strong son preference, a sex-selective abortion becomes therefore a much more important option.</p>\n\n\n\n<h4>Evidence from India</h4>\n\n\n\n<p>Seema Jayachandran (2017) tried to quantify how much of the skew in sex ratio in India might be attributed to the decline of the fertility rate in the country.{ref}Jayachandran, S. (2017). <a href=\"https://pubs.aeaweb.org/doi/pdfplus/10.1257/app.20150576\">Fertility decline and missing women</a>. <em>American Economic Journal: Applied Economics</em>, 9(1), 118-39.{/ref} In this visualization we summarize results from this research, through three charts:</p>\n\n\n\n<ul><li><strong>Left chart</strong>: we see the percentage of respondents of a survey in India who said they would prefer a son when given a hypothetical family size (number of children) from one to five i.e. having only one child; two children etc.{ref}The survey was actually posed to mothers and fathers of what they would want for their own children (who were all in secondary school at the time of the of survey). Asking it of a future hypothetical scenario helps to avoid hindsight bias.{/ref} Here we see that if they were having only one child, more than 80% of both mothers and fathers would prefer a son. This preference rapidly declines when they are asked about additional children; in fact, in the scenarios in which parents already have some sons parents preferred to have daughters.{ref}The reason for a switch to daughters is not totally clear. It&#8217;s suggested having daughters within larger families is preferred to provide care for others in the family and the household. It may also be the case that a larger number of sons creates tension and conflict with regards to resource allocation.{/ref} These results suggest that parents have a very strong preference to have a son if they have a small family.</li><li><strong>Middle chart</strong>: in red we see that the <em>desired fertility rate</em> \u2013 the number of children a woman desires to have \u2013 has declined in India in recent decades. At the same time, the child sex ratio \u2013 the number of males per 100 females \u2013 increased. The dashed line here shows the estimated change in sex ratio which results from falling fertility rates alone.</li><li><strong>Right chart</strong>: the blue line shows how the child sex ratio has increased over time. Shown in grey is the estimated increase in the sex ratio which can be attributed solely to the decline in fertility rates.</li></ul>\n\n\n\n<p>Seema Jayachandran (2017) results suggest that between one-third and one-half of the change in sex ratio in India since 1981 can be attributed to the decline in fertility rates. Or in other words: If there had been no change in fertility rates over time, there would still be a skew in the sex ratio. But fertility declines have had a significant impact on exacerbating son preference.</p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><a href=\"https://owid.cloud/app/uploads/2019/06/Fertility-impact-on-son-preference.png\"><img loading=\"lazy\" width=\"800\" height=\"364\" src=\"https://owid.cloud/app/uploads/2019/06/Fertility-impact-on-son-preference-800x364.png\" alt=\"\" class=\"wp-image-23713\" srcset=\"https://owid.cloud/app/uploads/2019/06/Fertility-impact-on-son-preference-800x364.png 800w, https://owid.cloud/app/uploads/2019/06/Fertility-impact-on-son-preference-150x68.png 150w, https://owid.cloud/app/uploads/2019/06/Fertility-impact-on-son-preference-400x182.png 400w, https://owid.cloud/app/uploads/2019/06/Fertility-impact-on-son-preference-768x349.png 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" /></a></figure></div>\n\n\n\n<h4>Development drives factors which can both increase and decrease gender preference</h4>\n\n\n\n<p>Disentangling a clear relationship between development and changes in the sex ratio is difficult because better education and rising incomes can impact aspects of gender selection in opposing ways.</p>\n\n\n\n<p>The reason is that the skewed sex ratio not only the result from the gender preference alone, but crucially also the ability to act upon it \u2013 by having a sex-selective abortion, for example. Kashyap and Villavicencio (2016) suggest that sex-selection practices result from three conditions being met:{ref}Kashyap, R., &amp; Villavicencio, F. (2016). <a href=\"https://link.springer.com/article/10.1007/s13524-016-0500-z\">The dynamics of son preference, technology diffusion, and fertility decline underlying distorted sex ratios at birth: A simulation approach</a>. <em>Demography</em>, 53(5), 1261-1281.{/ref}</p>\n\n\n\n<ol><li><em>willingness</em> to consider sex selection because you have a gender preference;</li><li><em>ability</em> to act upon it through access to prenatal sex-determination screening and abortion services;</li><li><em>readiness</em> to act upon it to get the desired sex preferences within the family.</li></ol>\n\n\n\n<p>How these three conditions change with development, education, and rising incomes can be in conflict. For example, research results suggest that higher education of the parents means a lower preference for a son.{ref}Jayachandran, S. (2017). <a href=\"https://pubs.aeaweb.org/doi/pdfplus/10.1257/app.20150576\">Fertility decline and missing women</a>. <em>American Economic Journal: Applied Economics</em>, 9(1), 118-39.{/ref} But, increased education is also associated with falling fertility rates and this decline in fertility (the &#8216;fertility squeeze&#8217;) increases son preference, as we explored above. Education therefore has two counteracting effects on the sex ratio: education decreases the <em>willingness</em> for gender preference, but increases the&nbsp;<em>readiness</em> for influencing sex preferences within the family.</p>\n\n\n\n<p>Development also affects condition (2): the ability to act upon gender preference. It is often the case that richer, urban families have greater access to technologies which would allow for sex identification during pregnancy, and also a safer abortion. Poorer families in rural areas may not have this opportunity, despite having strong son preference. As they get richer, these opportunities may become available to them.</p>\n\n\n\n<p>Kashyap and&nbsp;Villavicencio (2017) tried to model how the changes in&nbsp;<em>willingness</em>,&nbsp;<em>ability</em>, and&nbsp;<em>readiness</em> all affect the change in sex ratio in specific countries.{ref}Kashyap, R., &amp; Villavicencio, F. (2016). <a href=\"https://link.springer.com/article/10.1007/s13524-016-0500-z\">The dynamics of son preference, technology diffusion, and fertility decline underlying distorted sex ratios at birth: A simulation approach</a>. <em>Demography</em>, 53(5), 1261-1281.{/ref} They found that even very low levels of son preference can have a significant impact on the sex ratio if sex-selection technology diffuses steadily and fertility declines quickly. This means that in contexts where economic development is fast \u2013 meaning fertility rates fall quickly and prenatal screening technologies become widely accessible \u2013 even very small levels of son preference across a population can have a significant impact on the overall sex ratio.</p>\n\n\n\n<p>The relationship between development and sex ratio is complex and non-linear: what&#8217;s clear is that the issue does not quickly disappear through economic development alone.</p>\n\n\n\n<h3>Does banning prenatal practices reduce sex-selective abortion?</h3>\n\n\n\n<p>One of the three conditions for sex-selection is the <em>ability</em> to act upon gender practices through access to technology.</p>\n\n\n\n<p>Prenatal sex selection (PSS) relies on two technologies: prenatal sex determination (the ability to determine the sex of a foetus during pregnancy) and selective abortion.</p>\n\n\n\n<p>This raises the question of whether policies that aim to regulate prenatal sex determination and abortion have an impact on the prevalence of sex selection.</p>\n\n\n\n<p>Several governments limited prenatal sex selection through regulation when it became clear that sex selection was common and increasing. South Korea, China and India all implemented sex-selective abortion bans. Were they successful?</p>\n\n\n\n<p>Much of the literature on the topic suggests the bans alone were not effective enough to address the problem.{ref}Gupta, M. D. (2016). <a href=\"https://paa.confex.com/paa/2016/mediafile/ExtendedAbstract/Paper1728/banning%20prenatal%20sex-selection%20PAA%202016.pdf\">Is banning sex-selection the best approach for reducing prenatal discrimination?</a>. In <em>Population Association of America meeting</em>, Washington DC.{/ref}{ref}Subramanian, S. V., &amp; Selvaraj, S. (2009). <a href=\"https://jech.bmj.com/content/63/3/245.short\">Social analysis of sex imbalance in India: before and after the implementation of the Pre-Natal Diagnostic Techniques (PNDT) Act</a>. <em>Journal of Epidemiology &amp; Community Health</em>, 63(3), 245-252.{/ref}</p>\n\n\n\n<p>Looking at how the sex ratio at birth changed pre- and post-ban in each country also does not suggest that they were very effective. <strong>South Korea</strong>&nbsp;enacted a ban on prenatal sex identification in 1987/88. At this point the sex ratio at birth was around 110 male per 100 female births \u2013 as we see in the chart here. Following the introduction of the ban, the sex ratio continued to increase \u2013 reaching over 115 males per 100 female births in 1990 and maintaining a high ratio through the early 1990s.</p>\n\n\n\n<p>For <strong>China</strong> the evidence is similar.&nbsp;in 1994 \u2013 as part of its Law on Maternal and Infant Health Care \u2013 China introduced a ban of prenatal sex determination. As we see in this chart, the sex ratio at birth continued to increase after the introduction of the ban. In 1993 the ratio was 114 male per 100 female births; by the early 2000s this had increased to 118:100.</p>\n\n\n\n<p><strong>India&nbsp;</strong>introduced the Pre-Conception and Pre-Natal Diagnostic Techniques Act (PNDT) in 1994 which prohibited sex selection practices, including pre-screening to determine the sex of a fetus. In the decade which followed the introduction of the act, the sex ratio at birth did not improve.</p>\n\n\n\n<iframe style=\"width: 100%; height: 600px; border: 0px none;\" src=\"https://ourworldindata.org/grapher/sex-ratio-at-birth-males-chao-et-al\"></iframe>\n\n\n\n<p>At first glance, this would suggest that the banning of sex-selection practices was unsuccessful. The sex ratio continued to increase after their implementation.</p>\n\n\n\n<p>Whilst researchers agree that bans alone were not effective enough to stop the practice, many acknowledge that we don&#8217;t know the counterfactual scenario without a ban.{ref}Gupta, M. D. (2016). Is banning sex-selection the best approach for reducing prenatal discrimination?. In <em>Population Association of America meeting</em>, Washington DC.{/ref} Without a ban the sex ratio might have increased even further. Some studies have argued that bans were effective in preventing a worsening of gender imbalance, even if they didn&#8217;t reduce it.{ref}Nandi, A., &amp; Deolalikar, A. B. (2013). Does a legal ban on sex-selective abortions improve child sex ratios? Evidence from a policy change in India. Journal of Development Economics, 103, 216-228.{/ref}</p>\n\n\n\n<p>These policies may have had some impact on reducing the increase, but they clearly did not come close to ending the practice.<!----------------------------------><!----------------------------------><!----------------------------------><!----------------------------------></p>\n\n\n\n<h2>Definitions</h2>\n\n\n\n<p><strong>Sex ratio at birth</strong>: the number of males born per 100 females.</p>\n\n\n\n<p><strong>&#8216;Expected&#8217; sex ratio at birth</strong>: the expected sex ratio at birth is not completely equal: under ordinary circumstances we would expect there to be slightly more boys born than girls. This means that in all countries, births are male-biased. The <strong>expected sex ratio is approximately 105 boys born per 100 girls</strong>. This is the <a href=\"http://www.searo.who.int/entity/health_situation_trends/data/chi/sex-ratio/en/\">&#8216;natural&#8217; sex ratio reported by the World Health Organization</a> (WHO). There can be some variability in this expected ratio, ranging from around 102 to 107 boys per 100 girls. Having a male-biased sex ratio at birth therefore doesn&#8217;t necessarily represent gender discrimination, although much more skewed ratios (above 107 boys per 100 girls) does suggest the use of gender selection practices.</p>\n\n\n\n<p><strong>Prenatal sex selection</strong>: prenatal sex selection practices are those which are used to discriminate based on gender <em>during a woman&#8217;s pregnancy</em>. This requires the use of prenatal screening practices which can determine the sex of the fetus \u2013 this is often referred to as <strong>prenatal detection (PD)</strong>. This is followed by abortion in the case that it isn&#8217;t the desired sex.</p>\n\n\n\n<p><strong>Postnatal sex selection</strong>: postnatal sex selection is the discrimination based on gender&nbsp;<em>after the child has been born</em>. Postnatal sex selection can occur either directly through selective infanticide, or indirectly from the premature death of girls due to maltreatment, neglect or unequal treatment.</p>\n\n\n\n<p><strong>Infanticide</strong>:&nbsp;infanticide&nbsp;(or infant homicide) is the intentional killing of infants.</p>\n\n\n\n<h2>Data Sources</h2>\n\n\n\n<h4>World Bank</h4>\n\n\n\n<ul><li><strong>Data Source:</strong> World Bank \u2013 World Development Indicators</li><li><strong>Description of available measures:</strong>\n<ul>\n<li>Population female (% of total)</li>\n<li>Sex ratio at birth</li>\n<li>Child mortality, by sex</li>\n</ul>\n</li><li><strong>Time span:</strong> 1962-2017</li><li><strong>Geographical coverage:</strong> Global, by country</li><li><strong>Link:</strong>&nbsp;<a href=\"http://data.worldbank.org/data-catalog/world-development-indicators\">http://data.worldbank.org/data-catalog/world-development-indicators</a></li></ul>\n\n\n\n<h4>Chao et al. (2019)</h4>\n\n\n\n<ul><li><strong>Data Source:</strong> Chao, F., Gerland, P., Cook, A.R., Alkema, L. (2019). Systematic assessment of the sex ratio at birth for all countries and estimation of national imbalances and regional reference levels. <em>PNAS</em>.</li><li><strong>Description of available measures:</strong>\n<ul>\n<li>Sex ratio at birth (modelled estimates)</li>\n</ul>\n</li><li><strong>Time span:</strong> 1950-2017</li><li><strong>Geographical coverage:</strong> Global, by country</li><li><strong>Link:</strong>&nbsp;<a href=\"https://www.pnas.org/content/early/2019/04/09/1812593116\">https://www.pnas.org/content/early/2019/04/09/1812593116</a></li></ul>\n",
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    "excerpt": {
        "rendered": "How does the number of men and women differ between countries? And why?",
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    "date_gmt": "2019-06-13T11:27:56",
    "modified": "2023-05-14T18:45:38",
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    "authors_name": [
        "Hannah Ritchie"
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Links from other tables