Do psychosocial factors mediate sexual minorities’ risky sexual behavior? A twin study

Objectives: Risky sexual behavior among sexual minorities (lesbian, gay, and bisexual individuals) are partly attributed to mental health and other social disparities; but this may be confounded by correlated genetic and environmental influences. As preregistered, the present study investigated indirect associations between sexual minority status and increased lifetime sexual partners through increased psychosocial adversity (depressive and anxiety symptoms, intimate partner violence, and early life adversities) and substance use (alcohol, cannabis, and other illicit drugs), confounding by correlated genetic and environmental influences, and sex differences in these relationships. Method: The sample comprised sexual minority and heterosexual twins who participated in the first and second phases of the latest wave of data collection in the U.K. population-based Twins Early Development study cohort (June 2017 through February 2019; n = 9,697 and 8,718, respectively, Mage = 22.3 ± .92 years). Structural equation modeling was used to specify psychosocial adversity and substance use as mediators while genetic and environmental confounding was further determined by biometrical genetic analyses in which similarities in identical and nonidentical twins were compared. Results: Increased psychosocial adversity and substance use fully mediated increased lifetime sexual partners in sexual minority women while this effect was partial (31.1%) in men. The best-fitting genetic models indicated that these relationships were not confounded by correlated genetic and environmental influences. Conclusions: The relationships between sexual minority status, psychosocial adversity, substance use, and sexual health disparities appeared independent of genetic and environmental influences. Individual and systemic interventions to reduce psychosocial disadvantage and substance use can also decrease sexual health disparities among sexual minorities.