Sex-selective abortion

Sex-selective abortion ends a pregnancy because of the fetus’s predicted sex. Since the procedure is overwhelmingly used to abort female fetuses, the term often refers specifically to female-selective abortion. This practice is closely tied to female infanticide and is considered a form of violence against women by many human rights organizations.

Socioeconomic reasons for son preference and daughter aversion

It is most common in regions where sons are valued more than daughters, particularly parts of East Asia and South Asia—including China, India, and Pakistan—as well as the Caucasus, the Western Balkans, and, to a lesser extent, North America. Data from India’s third National Family and Health Survey showed that sex-selective abortion was more frequent when both parents, or just the father, preferred male children. When only the mother preferred sons, the result was more often sex-selective neglect, where the child was unlikely to survive infancy.

The practice was first recorded in 1975 and became widespread by the late 1980s in South Korea, Taiwan, and China, and around the same time or slightly later in India.

Sex-selective abortion alters the human sex ratio—the number of males compared to females in a given age group. This leads to a shortage of women, especially in China and India, the world’s two most populous countries.

Human sex ratio at birth

Many studies and reports assume that the birth-sex ratio—the overall ratio of boys to girls at birth in a region—is an indicator of sex-selective abortion. Some scholars have questioned this assumption. Researchers have estimated that in India, between 50,000 and 100,000 female fetuses are aborted each year, significantly affecting the sex ratio.

Recent research has broadened understanding by measuring trends in conditional sex ratios among Asian diaspora communities in Australia, Canada, the UK, and the US, showing that sex selection has continued in these groups from 1999 to 2019. Studies of the past four decades in China highlight how sex-selective abortion has shaped the country’s demographics, though exact numbers are hard to pin down due to underreporting and debate over the actual sex ratio at birth.

The expected natural birth-sex ratio is between 103 and 107 males per 100 females, with a 2002 estimate of 106. A ratio significantly different from 106 is often taken as evidence of sex-selective abortion—108 or higher suggesting female-selective abortion, and 102 or lower suggesting male-selective abortion. This assumption remains controversial and is the subject of ongoing scientific study.

A 2013 study found that in 35 of 61 surveyed countries, the sex ratio would exceed 110 males per 100 females if parents could choose their child’s sex.

High or low human sex ratio implies sex-selective abortion

One group of scholars argues that any birth-sex ratio outside the normal 105–107 range must be due to sex-selective abortion. They claim that both the birth ratio and the overall population sex ratio are remarkably stable in humans, so significant deviations can only come from manipulation.

In a widely cited article, Amartya Sen compared birth-sex ratios in Europe (106) and the United States (105) with those in Asia (107+) and argued that high ratios in East, West, and South Asia likely result from excessive female mortality. He noted that with equal nutrition and medical care, females survive better—males are the genetically frailer sex. Sen estimated that decades of high birth-sex ratios have created a female shortfall of 11% in Asia, or over 100 million missing women across South Asia, West Asia, North Africa, and China.

High or low human sex ratio may be natural

Other scholars question whether a birth-sex ratio outside 103–107 can occur naturally. William James and others challenge conventional assumptions: that mammalian sperm carry equal numbers of X and Y chromosomes, that X and Y have equal chances of conception, that equal numbers of male and female zygotes form, and that any variation in the birth ratio must come from sex selection between conception and birth. James cautions that the evidence contradicts these assumptions. He notes that an excess of males at birth is normal in nearly all human populations, with the natural ratio usually between 102 and 108, though it can deviate significantly.