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Sex-selective abortion is the practice of terminating a pregnancy based upon the predicted sex of the baby. The selective abortion of female fetuses is most common in areas where cultural norms value male children over female children, especially in parts of People's Republic of China, India, Pakistan, the Caucasus, and Southeast Europe.
Sex-selective abortion affects the human sex ratio — the relative number of males to females in a given age group. Studies and reports focusing on sex-selective abortion are predominantly statistical; they assume that birth sex ratio — the overall ratio of boys and girls at birth for a regional population, is an indicator of sex-selective abortion. This assumption has been questioned by some scholars. Scholars who support the assumption suggest that the expected birth sex ratio range is 103 to 107 males to females at birth. Countries considered to have significant practices of sex-selective abortion are those with birth sex ratios of 108 and above (selective abortion of females), and 102 and below (selective abortion of males). See list of countries by sex ratio.
Over 160 million females have been prevented from being born in Asia through sex selective abortion.
The earliest post-implantation test, cell free fetal DNA testing, involves taking a blood sample from the mother and isolating the small amount of fetal DNA that can be found within it. When performed after week seven of pregnancy, this method is about 98% accurate.
Obstetric ultrasonography, either transvaginally or transabdominally, checks for various markers of fetal sex. It can be performed at or after week 12 of pregnancy. At this point, 3⁄4 of fetal sexes can be correctly determined, according to a 2001 study. Accuracy for males is approximately 50% and for females almost 100%. When performed after week 13 of pregnancy, ultrasonography gives an accurate result in almost 100% of cases.
The most invasive measures are chorionic villus sampling (CVS) and amniocentesis, which involve testing of the chorionic villus (found in the placenta) and amniotic fluid, respectively. Both techniques typically test for chromosomal disorders but can also reveal the sex of the child and are performed early in the pregnancy. However, they are often more expensive and more dangerous than blood sampling or ultrasonography, so they are seen less frequently than other sex determination techniques.
Human sex ratio at birth for a region is the ratio of boys and girls born per year in a given regional population. In a 2002 study, the natural sex ratio at birth was estimated to be close to 106 boys to girls. Human sex ratio at birth that is significantly different than 106, is often assumed to be correlated to the prevalence and scale of sex-selective abortion. This assumption is controversial, and a subject of continuing scientific studies.
One school of scholars suggest that any birth sex ratio of boys to girls that is outside of the normal 105-107 range, necessarily implies sex-selective abortion. These scholars claim that both the sex ratio at birth and the population sex ratio are remarkably constant in human populations. Significant deviations in birth sex ratios from the normal range can only be explained by manipulation, that is sex-selective abortion. In a widely cited article, Amartya Sen compared the birth sex ratio in Europe (106) and United States (105) with those in Asia (107+) and argued that the high sex ratios in East Asia, West Asia and South Asia may be due to excessive female mortality. Sen pointed to research that had shown that if men and women receive similar nutritional and medical attention and good health care then females have better survival rates, and it is the male which is the genetically fragile sex. Sen estimated 'missing women' from extra women who would have survived in Asia if it had the same ratio of women to men as Europe and United States. According to Sen, the high birth sex ratio over decades, implies a female shortfall of 11% in Asia, or over 100 million women as missing from the 3 billion combined population of South Asia, West Asia, North Africa and China.
James cautions that available scientific evidence stands against the above assumptions and conclusions. He reports that there is an excess of males at birth in almost all human populations, and the natural sex ratio at birth is usually between 102 to 108. However the ratio may deviate significantly from this range for natural reasons such as early marriage and fertility, teenage mothers, average maternal age at birth, paternal age, age gap between father and mother, late births, ethnicity, social and economic stress, warfare, environmental and harmonal effects. This school of scholars support their alternate hypothesis with historical data when modern sex-selection technologies were unavailable, as well as birth sex ratio in sub-regions, and various ethnic groups of developed economies. They suggest that direct abortion data should be collected and studied, instead of drawing conclusions indirectly from human sex ratio at birth.
In the United States, the sex ratios at birth over the period 1970–2002 were 105 for the white non-Hispanic population, 104 for Mexican Americans, 103 for African Americans and Native Indians, and 107 for mothers of Chinese or Filipino ethnicity. Among Western European countries c. 2001, the ratios ranged from 104 to 107. In the aggregated results of 56 Demographic and Health Surveys in African countries, the birth sex ratio was found to be 103, though there is also considerable country-to-country, and year-to-year variation.
In a 2005 study, U.S. Department of Health and Human Services reported sex ratio at birth in the United States from 1940 over 62 years. This statistical evidence suggested the following: For mothers having their first baby, the total sex ratio at birth was 106 overall, with some years at 107. For mothers having babies after the first, this ratio consistently decreased with each additional baby from 106 towards 103. The age of the mother affected the ratio: the overall ratio was 105 for mothers aged 25 to 35 at the time of birth; while mothers who were below the age of 15 or above 40 had babies with a sex ratio ranging between 94 to 111, and a total sex ratio of 104. This United States study also noted that American mothers of Hawaiian, Filipino, Chinese, Cuban and Japanese ethnicity had the highest sex ratio, with years as high as 114 and average sex ratio of 107 over the 62 year study period. Outside of United States, European nations with extensive birth records, such as Finland, report similar variations in birth sex ratios over a 250 year period, that is from 1751 to 1997 AD.
In 2013, according to CIA estimates, some countries with high birth sex ratio were Liechtenstein (126), Curacao (115), Azerbaijan (113), Armenia (112), China (112), India (112), Vietnam (112), Georgia (111), Albania (111), Grenada (110), San Marino (109), Taiwan (109), Jersey (108), Kosovo (108), Macedonia (108) and Singapore (108). Low boys to girls birth sex ratios in 2013 were estimated by CIA for Haiti (101), Barbados (101), Bermuda (101), Cayman Islands (102), Qatar (102), Kenya (102), Malawi (102), Mozambique (102), South Africa (102) and Aruba (102).
The estimates for birth sex ratios, and thus derived sex-selective abortion, are a subject of dispute as well. For example, United States' CIA projects the birth sex ratio for Switzerland to be 106, while the Switzerland's Federal Statistical Office that tracks actual live births of boys and girls every year, reports the latest birth sex ratio for Switzerland as 107. Other variations are more significant; for example, CIA projects the birth sex ratio for Pakistan to be 105, United Nations FPA office claims the birth sex ratio for Pakistan to be 110, while the government of Pakistan claims its average birth sex ratio is 111.
The two most studied nations with high sex ratio and sex-selective abortion are China and India. The CIA estimates a birth sex ratio of 112 for both in recent years. However, The World Bank claims the birth sex ratio for China in 2009 was 120 boys for every 100 girls; while United Nations FPA estimates China's 2011 birth sex ratio to be 118. For India, the United Nations FPA claims a birth sex ratio of 111 over 2008-2010 period, while The World Bank and India's official 2011 Census reports a birth sex ratio of 108. These variations and data reliability is important as a rise from 108 to 109 for India, or 117 to 118 for China, each with large populations, represent a possible sex-selective abortion of about 100,000 girls.
Before the collapse of Soviet Union in early 1990s, the birth sex ratio in Caucasus countries such as Azerbaijan, Armenia and Georgia was in the 105 to 108 range. After the collapse, the birth sex ratios sharply climbed and have remained high for the last 20 years. In Christian Armenia and Islamic Azerbaijan currently more than 115 boys are born for every 100 girls, while in Christian Georgia the birth sex ratio is about 120, a trend claims The Economist that suggest sex-selective abortion practice in Caucasus has been similar to those in East Asia and South Asia in recent decades.
For 2005-2010 birth data, the sex ratio in Armenia is seen to be a function of birth order. Among couples having their first child, Armenia averages 138 boys for every 100 girls every year. If the first child is a son, the sex ratio of the second child of Armenian couple averages to be 85. If the first child is a daughter, the sex ratio of the second Armenian child averages to be 156 boys for 100 girls. Overall, the birth sex ratio for in Armenia exceeds 115, far higher than India's 108, claim scholars. While these high birth sex ratios suggest sex-selective abortion, there is no direct evidence of observed large scale sex-selective abortions in Caucasus.
|The neutrality of this section is disputed. (November 2013)|
When sex ratio began being studied in China in 1960, it was 106 males to 100 females, still within the normal range. However, it climbed to 111.9 by 1990 and 118 by 2010. Researchers believe that the causes of this sex ratio imbalance are increased female infant mortality, underreporting of female births and sex-selective abortion. According to Zeng et al. (1993), the most prominent cause is probably sex-selective abortion, but it is difficult to prove that in a country with so little reliable data because of the hiding of “illegal” (under the One-Child Policy) births. Therefore, there is extensive underreporting of female infants. However, they are eventually accounted for, as they must be registered for immunizations, education, etc. (To avoid the issue of underreporting, many studies use the sex ratio for those age 20 and younger.)
Traditional Chinese techniques have been used to determine sex for hundreds of years, primarily with unknown accuracy. It was not until ultrasonography became widely available in urban and rural China that sex was determined scientifically. In 1986, the Ministry of Health posted the Notice on Forbidding Prenatal Sex Determination, but it was not widely followed. Three years later, in 1989, the Ministry of Health outlawed all sex determination techniques, except for their use in diagnosing hereditary disease. However, many people still have personal connections to medical practitioners and strong son preference still dominates culture, leading to the widespread use of sex determination techniques. According to Hardy, Gu, and Xie (2000), ultrasound has spread to all areas of China, as evidenced by the spread of the high sex ratio throughout the country.
Additionally, they argue that if ultrasonography is available everywhere, sex-selective abortion will be more prevalent in rural China because son preference is so much stronger there. Urban areas of China, on average, are moving toward greater equality for both sexes. However, rural China tends to follow more traditional views of gender. For example, while sons are always part of the family, daughters are only temporary, going to a new family when they marry. Additionally, if a woman’s firstborn child is a son, her position in society moves up, while the same is not true of a firstborn daughter.
In years past, when families wanted a son, many would keep having children until they did, resulting in a normal sex ratio. However, the combination of financial concerns and the One-child policy (discussed further below) have led to an increase in gender planning and selection. Even in rural areas, most women know that ultrasonography can be used for gender discernment. For each subsequent birth, Junhong found that women are over 10% more likely to have an ultrasound (39% for firstborn, 55% for second born, 67% for third born). Additionally, he found that the sex of the firstborn child impacts whether a woman will have an ultrasound in her subsequent pregnancies: 40% of women with a firstborn son have an ultrasound for their second born child, versus 70% of women with firstborn daughters. This points to a strong desire to select for a son if one has not been born yet.
Junhong also found that many women don’t see a female child as a burden, but rather are pressured to produce a male son. Additionally, 85% of women would try to have two children, ideally one boy and one girl, if there were no restrictions on children. Most women will take steps to ensure their second child is a boy, if the first is a girl. However, they will not take steps to ensure their second child is a girl if the first is a boy, as it is too expensive.
Because of the lack of data about childbirth, a number of researchers have worked to learn about abortion statistics in China. One of the earliest studies by Qui (1987) found that according to cultural belief, fetuses are not thought of as human beings until they are born, leading to a cultural preference for abortion over infanticide. In fact, infanticide and infant abandonment are rather rare in China today. Junhong (2000) found that 27% of those surveyed had an abortion. Additionally, he found that if a family’s firstborn was a girl, 92% of known female would-be second born fetuses were aborted.
In a 2005 study, Zhu, Lu, and Hesketh found that the sex ratio for those ages 1–4 was highest overall, and only two provinces, Tibet and Xinjiang, had sex ratios within normal limits. Two provinces had a ratio over 140, four had ratios between 130-139, and seven had ratios between 120-129.
There are three types of provinces, which vary in restrictive nature of their childbearing laws. Type one is the most restrictive:
These provinces tend to be wealthier and more educated, and many parents have a pension to take care of them, eliminating the need for a son. Therefore, they have medium sex ratios and Winckler (2002) found that traditional gender preferences are changing toward more equality.
Type two provinces are less restrictive than type one:
These provinces tend to have more traditional structure and agriculturally-based economy, causing a need for a son. Therefore, sex ratio is highest in type two provinces.
Finally, type three provinces are the least restrictive:
These provinces are often poor and underpopulated and neither have a preference for sons nor believe in abortion, resulting in the lowest sex ratios.
Based on the relationship between type of province and sex ratio, many researchers believe making type two provinces into type one or three could dramatically lower the sex ratio.
Families in China are aware of the critical lack of female children and it’s implication on marriage prospects in the future; many parents are beginning to work extra when their sons are young so that they will be able to pay for a bride for them. Because of the rising awareness of the imbalance in China’s sex ratio, measures to lower it are beginning to take place. For example, in 2000, the Chinese government began the “Care for Girls” Initiative. The sex ratio among firstborn children in urban areas from 2000-2005 didn’t rise at all, so there is hope that this movement is taking hold across the nation.
In 2005, 1.1 million of excess males were born in China. Many males between the ages of 28 and 49 are unable to find a partner and thus remain unmarried. The South Korean and Chinese governments have had public campaigns against sex preference to reduce the disparity. Yet, these campaigns against male preference have had a mild impact in the female-male ratio in China. In South Korea, however, the impact was stronger with the rate going from 118 in 1990 to 109 in 2004. Currently, the gap between male-to-female birth ratios in China has decreased to 117 males born for every 100 females.
|The neutrality of this section is disputed. (November 2013)|
Abortions have been a popular medical procedure in India for quite some time, but the first law regarding abortion was not passed until 1971. This law, the Medical Termination of Pregnancy Act of 1971, made abortion legal in most states, but specified "acceptable" reasons for abortion, physicians who can provide the procedure, and the facilities they can be performed.[relevant? ] (Acceptable reasons included the pregnancy posing a serious risk to the mother, serious physical or mental disability of the fetus, the pregnancy being the result of a rape, etc.) Since the act was passed, more abortions have been performed illegally than legally for a variety of reasons, including cost, availability, "incorrect" reasons for abortion, desire for secrecy, etc. In 1996, Khan, Barge, and Philip estimated that of the 5-6 million abortions performed per year in India, 90% were performed illegally.
India’s second National Family Health Survey (NFHS-2), which compiled data from 1998-1999, found that, nationally, 2% of pregnancies ended in induced abortion, with higher rates in 25 of 26 states than found in the first survey (NFHS-1). However, many studies of the survey hypothesize that this number is a low estimate, as the full number of induced abortions was probably not reported (because of the number of abortions performed illegally). A sign of data inaccuracy was that the NFHS-2 showed higher rates of spontaneous abortion than NFHS-1. However, spontaneous abortions are primarily biologically and environmentally based, so they should not increase significantly over time. As a result, researchers have created higher estimates; Arnold, Kishor, and Roy believe that approximately 4.7% of Indian pregnancies ended in induced abortion in 2002.
Techniques for determining sex prenatally first became available in the early 1970s and quickly gained popularity. These techniques spread through most of the country very rapidly and today are typically available from mobile units (such as traveling ultrasound vans), although they have been banned for the purposes of sex determination since 1995. Sudha and Rajan (1999) found that sex determination techniques are sometimes packaged together with abortions and are often marketed as being cheaper in the long run, saving the family from a large dowry in the future, should the fetus be female. Although the Indian government and various female advocacy groups have tried to prevent sex selection, it remains a significant issue nationwide. There is evidence that such bans are rarely enforced and that numerous dedicated sex selection clinics operate in many regions of India. India’s prime minister has stated that gendercide is a national shame and its secretary of health and family welfare has acknowledged that the country has not been aggressive enough in combating it. Women's rights activists allege that the laws are not being enforced because the police and judiciary believe in and may even practice gendercide themselves. Moreover, there has been significant debate within India regarding the morality of sex selection. For example, there are arguments for sex selection which say that prenatal discrimination is more humane than postnatal discrimination, though there is little evidence that prenatal discrimination has any positive effect on postnatal discrimination; women are not necessarily held in higher regard if they are fewer in number.
India’s 2001 census revealed a national sex ratio of 107.8, up from 105.8 in the 1991 census. Because this number is an average, it masks even more dramatic numbers in certain states—Punjab’s ratio was 126.1, Haryana’s ratio was 122, and Gujarat’s ratio was 113.9, each of which represents a dramatic increase. Arnold, Kishor, and Roy hypothesize that this rapid increase was due to increased availability of sex determination techniques. In fact, Ganatra et al. (2000) found that 1⁄6 of all reported abortions followed a sex determination test. However, this alone does not show causation between sex determination testing and high sex ratios. Researchers also analyzed sex ratios in women who had undergone an induced abortion in the pregnancy just before their most recent live birth. This revealed a sex ratio of 158.0 in Punjab, Haryana, and Gujarat, significantly higher than rates elsewhere in the country. Moreover, these states have very high ultrasonography use and women in these states with no sons are more likely to have an ultrasound than women with at least one son. In Haryana, the sex ratio for babies born from mothers who had ultrasounds performed is 186.3, pointing to widespread sex determination among this population. This shows correlation between induced abortion and high sex ratios, probably pointing to the use of sex determination techniques.
India’s 2001 census found that the majority of southern states have a sex ratio at or approaching 105, the widely accepted “natural ratio.” In general, wealthier southern states have had sex ratios closer to 105 for quite some time. Gujarat, one of the states of interest with very high sex ratios in 2001, now has a child sex ratio around 112.8, an improvement since 2001 but not since 1991. Punjab, another state of interest, now has a child sex ratio of approximately 118.2, a small improvement since 2001. Finally, Haryana’s 2011 child sex ratio was 120.4, reflecting little improvement since 2001.
Overall, it is estimated that 6.4% of pregnancies with a female fetus are aborted, leading to a loss of approximately 106,000 female infants per year.
According to Eurostat and birth record data over 2008-2011, the birth sex ratios of Albania and Montenegro are currently 112 and 110 respectively. In recent years, the birth registration data for Macedonia and Kosovo indicate birth sex ratios above 108; for example, in 2011 the birth sex ratio was 108 in Macedonia, while in 2010 the birth sex ratio for Kosovo was 112. Scholars claim this suggests that sex-selective abortions are becoming common in southeast Europe.
Like in other countries, sex-selective abortion is difficult to track in the United States because of lack of data. However, based on the sex ratios in the United States, it is certainly rare for the population overall. Abrevaya (2009) found that =among firstborn children in the U.S., the sex ratio is the normal 102-106 males per 100 females. However, he also found that among some Korean, Chinese, and Indian parents with one daughter, the sex ratio is 117 and when they have two daughters, the ratio is 151.
While the majority of parents in United States do not practice sex-selective abortion, there is certainly a trend toward male preference. According to a 2011 Gallup poll, if they were only allowed to have one child, 49% of men and 31% of women would prefer a son. When told about prenatal sex selection techniques such as sperm sorting and in vitro fertilization embryo selection, 40% of Americans surveyed thought that picking embryos by sex was an acceptable manifestation of reproductive rights. These selecting techniques are available at about half of American fertility clinics, as of 2006.
However, it is notable that minority groups that immigrate into the United States bring their cultural views and mindsets into the country with them. A study carried out at a Massachusetts infertility clinic shows that the majority of couples using these techniques, such as Preimplantation genetic diagnosis came from a Chinese or Asian background. This is thought to branch from the social importance of giving birth to male children in China and other Asian countries.
Because of this movement toward sex preference and selection, many bans on sex-selective abortion have been proposed at the state and federal level. In 2010 and 2011, sex-selective abortions were banned in Oklahoma and Arizona, respectively. Legislators in Georgia, West Virginia, Michigan, Minnesota, New Jersey, and New York have also tried to pass acts banning the procedure.
A 2013 study by John Bongaarts based on surveys in 61 major countries calculates the sex ratios that would result if parents had the number of sons and daughters they want. In 35 countries, claims Bongaarts, the desired birth sex ratio in respective countries would be more than 110 boys for every 100 girls if parents in these countries actually get a gender what they hope for (higher than India’s, which The Economist claims is 108).
Abnormal sex ratios at birth, possibly explained by growing incidence of sex-selective abortion, have also been noted in some other countries outside South and East Asia. According to the 2011 CIA World Factbook, countries with more than 110 males per 100 females at birth also include Albania and former Soviet republics of Armenia and Azerbaijan. A 2005 study estimated that over 90 million females were "missing" from the expected population in Afghanistan, Bangladesh, China, India, Pakistan, South Korea and Taiwan alone, and suggested that sex-selective abortion plays a role in this deficit. India's 2011 census shows a serious decline in the number of girls under the age of seven - activists believe eight million female fetuses may have been aborted between 2001 and 2011.
Sex-selection practices also occur among some South Asian immigrants in the United States: A study of the 2000 United States Census observed definite male bias in families of Chinese, Korean and Indian immigrants, which was getting increasingly stronger in families where first one or two children were female. In those families where the first two children were girls, the sex ratio of the third child was observed to be 1.51:1 in favor of boys.
Some research suggests that culture plays a larger role than economic conditions in gender preference and sex-selective abortion, because such deviations in sex ratios do not exist in sub-Saharan Africa, Latin America, and the Caribbean. Demographers argue that perceived gender imbalances may arise from the underreporting of female births, rather than sex-selective abortion or infanticide.
The reason for intensifying sex-selection abortion in China and India can be seen through history and cultural background. Generally, before the information era, male babies were preferred because they provided manual labor and success the family lineage. Labor is still important in developing nations as China and India, but when it comes to family lineage, it is of great importance. The selective abortion of female fetuses is most common in areas where cultural norms value male children over female children. A son is often preferred as an "asset" since he can earn and support the family; a daughter is a "liability" since she will be married off to another family, and so will not contribute financially to her parents. The patriarchal structure of a society is the single most important factor skewing the sex ratio in favor of males, accentuated in some cultures by the burden of raising a dowry for a daughter's marriage. Openness to the very concept of sex selection is a significant factor: among societies which practice selective female abortion nowadays, many were systematically practicing female infanticide (either directly or by withholding postnatal care from children of undesirable sex) long before abortion became a viable option. Furthermore, in some cultures sons are expected to take care of their parents in their old age. In modern East Asia, a large part of the pattern of preferences leading to this practice can be condensed simply as a desire to have a male heir. Monica Das Gupta (2005) observes that, in late 1980s to early 1990s China, there was no evidence of selective abortion of female fetuses among firstborn children, or in families with one or more existing sons (in fact, families with multiple sons were, if anything, more likely to abort a boy than a girl). But, at the same time, families with existing daughters appeared very likely to abort any further female fetuses, resulting in heavily skewed sex ratios.
In many of the countries where there are high rates of sex-selective abortion, there are also high rates of sex-based inequality. India, which has one of the highest rates of sex-selective abortion in the world, has also recently been plagued with news reports about high rates of rape, as well as a lack of police interference or investigation after a rape has been reported. As well as acts of physical violence against women, they generally have a lower status in society, receiving less education and fewer, or lower paid jobs than men. This further reduces their status within society, because it results in dependence on men.
Also, males are viewed as an economic asset in a poorer household, for they help with work on farms, they will take care of their parents as they age, and they do not require a dowry for marriage.
Many feminists argue, however, that this boils down to do objectification of female bodies, and the view that women are less important than men. Sex-selective abortion, therefore, can be seen as an extension of sexism within these cultures. It is determining that one gender (generally male) is more worthy of life than the other. Many feminists also argue that sex-selective abortion exacerbates sexism, because it validates the idea that people can deprive someone of life simply for being a woman. This results in a vicious cycle, where sexism fuels the need for a male line, and sex-selective abortion endorses the superiority of men.
Following the 1949 creation of the People's Republic of China, the issue of population control came into the national spotlight. In the early years of the Republic, leaders believed that telling citizens to reduce their fertility was enough, repealing laws banning contraception and instead promoting its use. However, the contraceptives were not widely available, both because of lack of supply and because of cultural taboo against discussing sex. Efforts were slowed following the famine of 1959-1961 but were resumed shortly thereafter with virtually the same results. Then, in 1964, the Family Planning Office was established to enforce stricter guidelines regarding fertility and it was moderately successful.
In 1980, Chairman Mao Zedong instituted the One-Child Policy, which limits many families to one child, unless specified by provincial regulations. It was instituted as an attempt to boost the Chinese economy. Under it, families who break rules regarding the number of children they are allowed are given various punishments (primarily monetary), dependent upon the province in which they live.
As stated above, the sex ratios of a province are largely determined by the type of restriction placed upon the family, pointing to the conclusion that much of the imbalance in sex ratio in China can be attributed to the policy. Research by Junhong (2001) found that many parents are willing to pay to ensure that their child is male (especially if their first child is female), but will not do the same to ensure their child is female. Likely, fear of the harsh monetary punishments of the One-Child Policy make ensuring a son’s birth a smart investment. Therefore, son’s cultural and economic importance to families and the large expenses associated with multiple children are primary factors leading to China’s disparate sex ratio.
In November 2013, China announced plans to ease restrictions of the One-Child Policy.
The Trivers–Willard hypothesis argues that available resources affect male reproductive success more than female and that consequently parents should prefer males when resources are plentiful and females when resources are scarce. This has been applied to resource differences between individuals in a society and also to resource differences between societies. Empirical evidence is mixed with higher support in better studies according to Cronk in a 2007 review. One example, in a 1997 study, of a group with a preference for females was Romani in Hungary, a low status group. They "had a female-biased sex ratio at birth, were more likely to abort a fetus after having had one or more daughters, nursed their daughters longer, and sent their daughters to school for longer."
Gender-linked genetic abnormalities, such as several forms of colorblindness, are linked to recessive genes on the X chromosome. Pre-implantation genetic diagnosis can identify some life-threatening genetic abnormalities in embryo. The easiest way to select against embryos which may have a gender-linked genetic abnormality is to choose only female embryos. Embryos which are not implanted are usually discarded.
According to work by Amartya Sen (1990), China’s disparate sex ratio caused there to be about 11% fewer women in China than there should be (according to the natural sex ratio). This translates to 50 million missing women in China alone, resulting in a critical shortage of wives. Combined with the sex ratios in South Asia, West Asia, and North Africa, there are over 100 million missing women worldwide. As a result, there are reports of women from Vietnam, Myanmar, and North Korea systematically trafficked to mainland China and Taiwan and sold into forced marriages. In South Korea and Taiwan, high male sex ratios and declining birth rates over several decades have led to cross-cultural marriage between local men and foreign women from countries such as mainland China, Vietnam and the Philippines.
Some argue that sex-selective abortion will actually lead to women gaining a higher position in society. For instance, Park and Cho (1995) say that when women are in smaller supply (as will be the case in the future in nations with high sex ratios), they will be more valued. However, most say that this is not the case—even when there are few women, they are still trafficked. In fact, some argue that trafficking may actually get worse when there are fewer women, as men will be willing to go to more elaborate measures to get women.
In 1994 over 180 states signed the Programme of Action of the International Conference on Population and Development, agreeing to "eliminate all forms of discrimination against the girl child". In 2011 the resolution of PACE's Committee on Equal Opportunities for Women and Men condemned the practice of prenatal sex selection.
On the state level, laws against sex-selective abortions have been passed in a number of US states; the law passed in Arizona in 2011 prohibits both sex-selective and race-selective abortion.