Pergament Eugene, Toydemir Pinar Bayrak, Fiddler Morris
Department of Obstetrics and Gynecology, Northwestern University, Chicago, IL, USA.
Reprod Biomed Online. 2002 Jul-Aug;5(1):43-6. doi: 10.1016/s1472-6483(10)61596-9.
The primary sex ratio in humans differs remarkably from the theoretically expected equality of 1:1, and may be as high as 170 males to 100 females. A number of environmental, physiological and genetic factors have been observed to impact on the primary sex ratio: sexual behaviour, variation in hormonal concentrations, natural disasters, environmental pollutants and timing of conception. Nevertheless, no biological mechanism or interaction of factors has suitably explained this phenomenon, or that of the prenatal vulnerability of the male, the suspected higher sex ratio in spontaneous abortion and the male excesses in adult diseases related to the intrauterine environment. Knowledge of the environmental effects and causes of natural variation in the primary sex ratio will make possible its manipulation, which will have public health implications as well as cultural and social consequences.
人类的出生性别比与理论上预期的1:1平等情况有显著差异，可能高达每100名女性对应170名男性。人们观察到许多环境、生理和遗传因素会影响出生性别比：性行为、激素浓度变化、自然灾害、环境污染物以及受孕时间。然而，尚无生物学机制或因素间的相互作用能够充分解释这一现象，以及男性在出生前的脆弱性、自然流产中疑似较高的性别比，还有与子宫内环境相关的成人疾病中男性占比过高的现象。了解环境对出生性别比自然变化的影响及成因将使其得以调控，这将产生公共卫生影响以及文化和社会后果。
