Department of Psychology, Memorial University of Newfoundland, St. Johns, NL A1B 3X9, Canada.
Neuroscience Program, Michigan State University, United States of America.
Horm Behav. 2020 Apr;120:104686. doi: 10.1016/j.yhbeh.2020.104686. Epub 2020 Feb 6.
On average, the length of the index finger (digit 2) divided by the length of the ring finger (digit 4) on the right hand, is greater in women than in men. Converging evidence makes it clear that prenatal androgens affect the development of digit ratios in humans and so are likely responsible for this sex difference. Thus, differences in 2D:4D between groups within a sex may be due to average differences between those groups in prenatal androgen exposure. There have been many reports that lesbians, on average, have a smaller (more masculine) digit ratio than straight women, which has been confirmed by metaanalysis. These findings indicate that lesbians were, on average, exposed to greater prenatal androgen than straight women, which further indicates that greater levels of prenatal androgen predispose humans to be attracted to women in adulthood. Nevertheless, these results only apply to group differences between straight women and lesbians; digit ratios cannot be used to classify individual women as gay or straight.
平均而言，右手食指（第 2 指）与无名指（第 4 指）的长度之比，女性大于男性。越来越多的证据表明，产前雄激素会影响人类手指比例的发育，因此很可能是造成这种性别差异的原因。因此，同一性别内不同组之间的 2D:4D 差异可能是由于这些组在产前雄激素暴露方面存在平均差异。有许多报告称，女同性恋者的手指比例（更男性化）平均小于直女，这已被荟萃分析所证实。这些发现表明，女同性恋者在平均水平上受到的产前雄激素比直女多，这进一步表明，较高水平的产前雄激素使人在成年后更容易被女性吸引。然而，这些结果仅适用于直女和女同性恋者之间的群体差异；手指比例不能用于将个别女性归类为同性恋或异性恋。
