Background: Female youth who describe their sexual orientation as "mostly heterosexual," rather than exclusively heterosexual, display greater sexual risk, yet reasons for this greater risk are not understood. Research is needed to identify factors responsible for health disparities in this population comprising the majority of youth who report a minority sexual orientation.
Methods: We compared indicators of perceived social support, parental/caregiver mental health, and sexual risk (age at first sexual intercourse, lifetime history of a sexually transmitted infection (STI), lifetime number of sexual partners) among 33 young women describing themselves as mostly heterosexual and 337 indicating they were 100% heterosexual (aged 18-24 years) participating in an urban, multiethnic, community-based cohort study. Linear, logistic, and Cox proportional hazards regression were used to test whether social support and caregiver mental health explained greater sexual risk among mostly heterosexual compared with heterosexual participants.
Results: Compared with exclusively heterosexuals, mostly heterosexuals reported less social support from family (p=0.01) and friends (p=0.02) and were more likely to report primary male caregiver (though not primary female caregiver) histories of depression (p<0.0001), treatment for depression (p<0.0001), and problems with drug use (p=0.005). Differences in perceived family social support and caregiver mental health and substance use partially mediated relationships between sexual orientation and sexual risk.
Conclusions: Compared with exclusively heterosexual female youth, mostly heterosexual female youth may have poorer relationships with their family and others in their social networks, and this may contribute to their elevated health risks. Additional research is needed to understand causal mechanisms responsible for sexual orientation disparities in sexual risk.