Waldron Mary, Heath Andrew C, Turkheimer Eric, Emery Robert, Bucholz Kathleen K, Madden Pamela A F, Martin Nicholas G
Department of Psychiatry, Washington University School of Medicine, St Louis, Missouri 63110, United States of America.
Twin Res Hum Genet. 2007 Jun;10(3):440-9. doi: 10.1375/twin.10.3.440.
Girls who report first sexual intercourse during their early teen years have much higher rates of teenage pregnancy and childbearing than girls who delay sexual onset until older adolescence. In this study, we examine genetic and environmental influences on variation in teenage pregnancy and covariation with age at first sexual intercourse in two cohorts of Australian female twins. In the older twin cohort, born 1893-1964, we observe substantial heritable variation in teenage pregnancy that is largely shared with heritable variation in age at first sexual intercourse, with shared environment contributing little to variation in teenage pregnancy. Genetic influences on teenage pregnancy are smaller and nonsignificant in the younger twin cohort, born 1964-1971, where shared environment contributes much more and overlaps entirely with shared environmental variation in age at first intercourse.
与那些将首次性行为推迟到青春期后期的女孩相比，在青少年早期就经历首次性行为的女孩有更高的青少年怀孕和生育几率。在本研究中，我们在两组澳大利亚女性双胞胎队列中，考察了遗传和环境因素对青少年怀孕差异的影响，以及与首次性行为年龄的协变关系。在出生于1893年至1964年的年龄较大的双胞胎队列中，我们观察到青少年怀孕存在显著的遗传变异，且这种变异在很大程度上与首次性行为年龄的遗传变异相同，而共享环境对青少年怀孕差异的影响很小。在出生于1964年至1971年的年龄较小的双胞胎队列中，遗传因素对青少年怀孕的影响较小且不显著，在这个队列中，共享环境的影响更大，并且与首次性行为年龄的共享环境变异完全重叠。
