Local Sex Ratios and Concurrent Sexual Partnerships in the U.S.

Kate W. Strully, University at Albany, State University of New York (SUNY)
Matthew Vogel, University at Albany, State University of New York (SUNY)

Temporally overlapping (i.e., concurrent) sexual partnerships facilitate the transmission of STDs within a population. Sex ratio theories and qualitative evidence suggest that concurrent partnerships will be more common when sex ratios are skewed, particularly among the scarcer (i.e., outnumbered) gender group. However, associations between sex ratios and concurrent partnerships have not been systematically tested at the national level within the U.S. This analysis begins to address this deficit, drawing on data from the U.S. National Longitudinal Survey of Adolescent Health (Add Health). After exploring the relationship between sex ratios and number of sexual partnerships, we test whether local (i.e., school and neighborhood) sex ratios: (i) affect the likelihood of concurrent partnerships; (ii) help account for race and gender differences in concurrent partnerships; and (iii) have varying associations with concurrent partnerships depending on respondents’ race or gender.