Evidence that prenatal testosterone transfer from male twins reduces the fertility and socioeconomic success of their female co-twins
Evidence that prenatal testosterone transfer from male twins reduces the fertility and socioeconomic success of their female co-twins
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DOI：
10.1073/pnas.1812786116
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发表时间：
2019-04-02
影响因子：
11.1
通讯作者：
Salvanes, Kjell G.
中科院分区：
文献类型：
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作者：
Butikofer, Aline;Figlio, David N.;Salvanes, Kjell G.
在子宫内的敏感时期，性腺类固醇有助于组织人类和其他哺乳动物的生物性别差异。在产仔物种中，被动暴露于同窝雄性产前睾酮的染色体雌性在成年后表现出身体和行为特征的改变。这种影响对人类造成的后果尚不清楚，但自 1980 年以来，许多国家的双胞胎率几乎翻了一番，这是由于高龄产妇和对体外受精的依赖增加所致，这意味着许多人口中越来越多的女性可能会接触到来自男性双胞胎的产前睾酮。在这里，我们使用 1967 年至 1978 年间挪威所有新生儿（n = 728,842，包括 13,800 双胞胎）的数据来表明，在子宫内与男性同卵双胞胎接触的女性高中毕业 (15.2%)、完成大学学业 (3.9%) 和结婚 (11.7%) 的概率降低，生育率 (5.8%) 和生命周期收入也较低（8.6%）。在 583 名和 239 名女性的亚组中，这些关系保持不变，她们的男性双胞胎分别在出生后第一年和生命的前 28 天死亡，支持这样的解释：这些关系主要是由于产前接触，而不是与兄弟姐妹一起抚养的产后社会化影响。我们的研究结果提供了经验证据，使用客观测量的国家级数据表明，产前接触男性双胞胎的人类女性在婚姻、生育和人力资本方面经历了长期变化。这些发现支持了双胞胎之间子宫内睾酮转移的假设，这可能会影响全世界一小部分但不断增长的女性。
During sensitive periods in utero, gonadal steroids help organize biological sex differences in humans and other mammals. In litter-bearing species, chromosomal females passively exposed to prenatal testosterone from male littermates exhibit altered physical and behavioral traits as adults. The consequences of such effects are less well understood in humans, but recent near-doubling of twinning rates in many countries since 1980, secondary to advanced maternal age and increased reliance on in vitro fertilization, means that an increasing subset of females in many populations may be exposed to prenatal testosterone from their male co-twin. Here we use data on all births in Norway (n = 728,842, including 13,800 twins) between 1967 and 1978 to show that females exposed in utero to a male co-twin have a decreased probability of graduating from high school (15.2%), completing college (3.9%), and being married (11.7%), and have lower fertility (5.8%) and life-cycle earnings (8.6%). These relationships remain unchanged among the subsets of 583 and 239 females whose male co-twin died during the first postnatal year and first 28 days of life, respectively, supporting the interpretation that they are due primarily to prenatal exposure rather than to postnatal socialization effects of being raised with a male sibling. Our findings provide empirical evidence, using objectively measured nation-level data, that human females exposed prenatally to a male co-twin experience long-term changes in marriage, fertility, and human capital. These findings support the hypothesis of in utero testosterone transfer between twins, which is likely affecting a small but growing subset of females worldwide.