Department of Genetics, Evolution and Environment, University College London, London, UK.
Paediatr Perinat Epidemiol. 2012 May;26(3):181-9. doi: 10.1111/j.1365-3016.2012.01267.x.
The human sex ratio (proportion male at birth) shows considerable variation which is central to reproductive epidemiology. For example, it has reportedly shown significant secular trends and wartime variation, and it has shown replicated variation with parental exposure to several deleterious chemicals. However, scientific progress in identifying the causes of these forms of variation has been very slow and, as described here, this has elicited some scepticism. Benefits may be expected from identifying these causes. Two (non-competing) hypotheses have emerged, the first relating to the hormonal regulation of sex ratio at conception, and the second to the sex-selective effects of stressors during pregnancy. It is shown here that if the first of these hypotheses was substantially correct, it would illuminate a number of scientific and medical problems, for example, the causes of autism and of selected sex-related congenital malformations and obstetric pathologies.
人类性别比例（出生时男性比例）存在相当大的差异，这是生殖流行病学的核心问题。例如，据报道，它显示出显著的长期趋势和战时变化，并且随着父母接触到几种有害化学物质的变化而得到了复制。然而，在确定这些变异形式的原因方面，科学进展非常缓慢，正如这里所描述的，这引起了一些怀疑。从确定这些原因中可能会获得好处。已经出现了两个（非竞争）假设，第一个与受孕时性别比例的激素调节有关，第二个与怀孕期间应激源的性别选择性效应有关。这里表明，如果第一个假设在很大程度上是正确的，它将阐明许多科学和医学问题，例如自闭症以及某些与性别相关的先天性畸形和产科病理的原因。
