The Economist has analysed data from the un’s World Population Prospects, a biennial report, and from China’s 2020 census. The data reveal that the sex ratio–the number of men for every 100 women–among men aged 23-37 and women aged 22-36 will hit a peak of 119 by 2027. (Those are the ages between which 80% of each sex gets married–see chart 1.) It is then predicted to remain high for decades. In 2012 the ratio was just 105.
It was brought about by the arrival in the 1980s of cheap ultrasound machines, which allowed parents across Asia to tell the sex of their unborn child. The widespread preference for sons opened the door to sex-selective abortions. In South Korea the sex ratio at birth hit a brief peak of 117 in 1994, before falling to 106 in 2012, where it has roughly remained. In India it was 109 as late as 2010 (in 2024 it was 107). In developed countries like America and Britain, it was around 105 in 2024. [emphasis added]