Sex-selective abortion

World map of birth sex ratios, 2012

Sex-selective abortion is the practice of terminating a pregnancy based upon the predicted sex of the infant. The selective abortion of female fetuses is most common where male children are valued over female children, especially in parts of East Asia and South Asia (particularly in countries such as People's Republic of China, India and Pakistan), North America, as well as in the Caucasus, and Western Balkans.[1][2][3]

Sex selective abortion was first documented in 1975,[4] and became commonplace by the late 1980s in South Korea and China and around the same time or slightly later in India.

Sex-selective abortion affects the human sex ratio—the relative number of males to females in a given age group,[5][6] with China and India, the two most populous countries of the world, having unbalanced gender ratios. 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.[7]

According to demographic scholarship, the expected birth sex ratio range is 103 to 107 males to 100 females at birth.[8][9]

Human sex ratio at birth

The human sex ratio at birth can vary for natural reasons as well as from sex-selective abortion. In many nations abortion is legal (see above map, dark blue).

Sex-selective abortion affects the human sex ratio—the relative number of males to females in a given age group.[5] Studies and reports that discuss sex-selective abortion are based on the assumption that birth sex ratio—the overall ratio of boys and girls at birth for a regional population, is an indicator of sex-selective abortion.[7][10]

The natural human sex ratio at birth was estimated, in a 2002 study, to be close to 106 boys to 100 girls.[11] Human sex ratio at birth that is significantly different from 106 is often assumed to be correlated to the prevalence and scale of sex-selective abortion. 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).[8] This assumption is controversial, and the subject of continuing scientific studies.

High or low human sex ratio implies sex-selective abortion

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[12] 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.[13]

In a widely cited article,[14] 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.[9]

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.

High or low human sex ratio may be natural

Other scholars question whether birth sex ratio outside 103–107 can be due to natural reasons. William James and others[7][15] suggest that conventional assumptions have been:

  • there are equal numbers of X and Y chromosomes in mammalian sperms
  • X and Y stand equal chance of achieving conception
  • therefore equal number of male and female zygotes are formed, and that
  • therefore any variation of sex ratio at birth is due to sex selection between conception and birth.

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 and 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 hormonal effects.[7][16] 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.[17][18] They suggest that direct abortion data should be collected and studied, instead of drawing conclusions indirectly from human sex ratio at birth.

James' hypothesis is supported by historical birth sex ratio data before technologies for ultrasonographic sex-screening were discovered and commercialized in the 1960s and 1970s, as well by reverse abnormal sex ratios currently observed in Africa. Michel Garenne reports that many African nations have, over decades, witnessed birth sex ratios below 100, that is more girls are born than boys.[19] Angola, Botswana and Namibia have reported birth sex ratios between 94 and 99, which is quite different than the presumed 104 to 106 as natural human birth sex ratio.[20]

John Graunt noted that in London over a 35-year period in the 17th century (1628–62),[21] the birth sex ratio was 1.07; while Korea's historical records suggest a birth sex ratio of 1.13, based on 5 million births, in 1920s over a 10-year period.[22] Other historical records from Asia too support James' hypothesis. For example, Jiang et al. claim that the birth sex ratio in China was 116–121 over a 100-year period in the late 18th and early 19th centuries; in the 120–123 range in the early 20th century; falling to 112 in the 1930s.[23][24]

Data on 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 Americans, and 107 for mothers of Chinese or Filipino ethnicity.[25] Among Western European countries c. 2001, the ratios ranged from 104 to 107.[26][27][28] In the aggregated results of 56 Demographic and Health Surveys[29] 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.[30]

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.[31] 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 and 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.[18]

In 2017, according to CIA estimates,[32] the countries with the highest birth sex ratio were Liechtenstein (125), Northern Mariana Islands (116), China (114), Armenia (112), Falkland Islands (112), India (112), Grenada (110), Hong Kong (110), Vietnam (110), Albania (109), Azerbaijan (109), San Marino (109), Isle of Man (108), Kosovo (108) and Macedonia (108). Also in 2017 the lowest ratio (ie. more girls born) was in Nauru at (0.83).[32] There were ratios of 102 and below in several countries, most of them African countries or Black/African majority population Caribbean countries: Angola, Aruba, Barbados, Bermuda, Burkina Faso, Burundi, Cabo Verde, Cameroon, Cayman Islands, Central African Republic, Chad, Comoros, Republic of the Congo, Cote d'Ivoire, Djibouti, Eritrea, Eswatini, Ethiopia, Gabon, The Gambia, Ghana, Guinea-Bissau, Haiti, Kazakhstan, Leshoto, Liberia, Madagascar, Malawi, Mali, Mauritania, Mozambique, Niger, Puerto Rico, Qatar, Senegal, Sierra Leone, Somalia, South Africa, Togo, Uganda, Zambia.[32]

There is controversy about the notion of the exact natural sex ratio at birth. In a study around 2002, the natural sex ratio at birth was estimated to be close to 1.06 males/female.[33] There is controversy whether sex ratios outside the 103-107 range are due to sex-selection, as suggested by some scholars, or due to natural causes. The claims that unbalanced sex ratios are necessary due to sex selection have been questioned by some researchers.[7] Some researchers argue that an unbalanced sex ratio should not be automatically held as evidence of prenatal sex-selection; Michel Garenne reports that many African nations have, over decades, witnessed birth sex ratios below 100, that is more girls are born than boys.[19] Angola, Botswana and Namibia have reported birth sex ratios between 94 and 99, which is quite different than the presumed "normal" sex ratio, meaning that significantly more girls have been born in such societies.[20]

In addition, in many developing countries there are problems with birth registration and data collection, which can complicate the issue.[34] With regard to the prevalence of sex selection, the media and international attention has focused mainly on a few countries, such as China, India and the Caucasus, ignoring other countries with a significant sex imbalance at birth. For example, Liechtenstein's sex ratio is far worse than that of those countries, but little has been discussed about it, and virtually no suggestions have been made that it may practice sex selection, although it is a very conservative country where women could not vote until 1984.[35][36] At the same time, there have been accusations that the situation in some countries, such as Georgia, has been exaggerated.[37] In 2017, Georgia' sex ratio at birth was 107, according to CIA statistics.[38]

Data reliability

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[39] 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.[40] Other variations are more significant; for example, CIA projects[39] the birth sex ratio for Pakistan to be 105, United Nations FPA office claims[41] the birth sex ratio for Pakistan to be 110, while the government of Pakistan claims its average birth sex ratio is 111.[42][43]

The two most studied nations with high sex ratio and sex-selective abortion are China and India. The CIA estimates[39] 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;[44] while United Nations FPA estimates China's 2011 birth sex ratio to be 118.[45]

For India, the United Nations FPA claims a birth sex ratio of 111 over 2008–10 period,[45] while The World Bank and India's official 2011 Census reports a birth sex ratio of 108.[46][47] 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.