Sexual Orientation and Age at Menarche in Three U.S. Longitudinal Cohorts

PURPOSE: The aim of this study is to examine age at menarche across sexual orientation groups. METHODS: Data were obtained from 131,090 female participants, born 1947-2001, in 3 longitudinal studies-the Growing Up Today Study and Nurses\u27 Health Study 2 and 3. We estimated the association between sexual orientation and age at menarche using regression models adjusted for age, race/ethnicity, birthweight, height, and body mass index. RESULTS: Compared to heterosexual participants, sexual minorities were younger at menarche. Sexual minorities were more likely to have early menarche (≤11 years) and less likely to have late menarche (≥14 years) compared to heterosexual girls. As an example of this pattern, Nurses\u27 Health Study 3 bisexual participants were \u3e30% more likely than heterosexuals to have early versus average menarche (odds ratio 1.37, 95% confidence interval 1.09-1.72). CONCLUSION: Sexual minority girls have a younger age at menarche than heterosexual girls and may benefit from screening for adverse outcomes associated with early menarche