The Galton Laboratory, Department of Genetics, Evolution and Environment, University College London, UK.
J Biosoc Sci. 2010 Sep;42(5):587-99. doi: 10.1017/S002193201000012X. Epub 2010 Jun 3.
The human sex ratio SR (proportion male) at birth has been reported to vary with many variables. The explanation of this variation is not established, but I have hypothesized that it is partially caused by the hormonal concentrations of both parents around the time of conception. The present note suggests how this hypothesis might accommodate recent sex ratio findings relating to 'psychosexual restriction', female genital cutting, sexes of prior sibs, finger length ratios, the autism spectrum disorder, parental occupation and maternal eating disorders. Tests of such suggestions are offered, and it is hypothesized that: (a) in women, Manning's R (the ratio of the lengths of the 2nd and 4th digits) is positively correlated with offspring sex ratio (proportion male); (b) women who have undergone female genital cutting (FGC) have high androgen levels; (c) offspring sex ratio correlates positively with 'masculinity' of parental occupation, the correlation being mediated by testosterone levels. It is noted that the lines of evidence for three hypotheses (James', Manning's and Baron-Cohen's) are mutually supportive.
人类出生时的性别比例 SR（男性比例）据报道会受到许多变量的影响。这种变化的解释尚未确定，但我假设它部分是由父母双方在受孕时的激素浓度引起的。本说明提出了这个假设如何适应最近与“性心理限制”、女性生殖器切割、同胞前的性别、手指长度比、自闭症谱系障碍、父母职业和母亲饮食失调有关的性别比例发现。提供了对这些建议的测试，并假设：(a) 在女性中，曼宁的 R（第 2 和第 4 指长度的比例）与后代的性别比例（男性比例）呈正相关；(b) 接受过女性生殖器切割 (FGC) 的女性雄激素水平较高；(c) 后代的性别比例与父母职业的“男性化”呈正相关，这种相关性是由睾丸激素水平介导的。值得注意的是，三个假设（詹姆斯、曼宁和巴伦-科恩）的证据相互支持。
