Abnormal sex ratios in human populations: Causes and consequences

摘要: In the absence of manipulation, both sex ratio at birth and population are remarkably constant in human populations. Small alterations do occur naturally; for example, a small excess male births has been reported to during after war. The tradition son preference, however, distorted these natural ratios large parts Asia North Africa. This preference is manifest sex-selective abortion discrimination care practices girls, which lead higher female mortality. Differential gender mortality documented problem decades led reports early 1990s 100 million "missing women" across developing world. Since that time, improved health conditions women have resulted reductions mortality, but advances now offset by huge increase use abortion, became available mid-1980s. Largely as result this practice, there an estimated 80 missing females India China alone. cohorts "surplus" males reaching adulthood predominantly low socioeconomic class, concerns expressed their lack marriageability, consequent marginalization society, may antisocial behavior violence, threatening societal stability security. Measures reduce selection must include strict enforcement existing legislation, ensuring equal rights women, public awareness campaigns about dangers imbalance.