Objectives. We examined sexual-orientation disparities in frequent engagement in cancer-related risk indicators of tobacco, alcohol, diet and physical activity, ultraviolet radiation, and sexually transmitted infections (STIs).

Methods. We used longitudinal data from the national Growing Up Today Study (1999–2010). Of the analytic sample (n = 9958), 1.8% were lesbian or gay (LG), 1.6% bisexual (BI), 12.1% mostly heterosexual (MH), and 84.5% completely heterosexual (CH).

Results. More sexual minorities (LGs, BIs, and MHs) than CHs frequently engaged in multiple cancer-related risk behaviors (33%, 29%, 28%, and 19%, respectively). Sexual-minority young women, especially BI and MH, more frequently engaged over time in substance use and diet and physical activity risk than CH women. More young gay than CH men frequently engaged over time in vomiting for weight control (odds ratio [OR] = 3.2; 95% confidence interval [CI] = 1.1, 9.4), being physically inactive (OR = 1.7; 95% CI = 1.2, 2.4), and using tanning booths (OR = 4.7; 95% CI = 3.0, 7.4), and had a higher prevalence of ever having an STI (OR = 3.5; 95% CI = 2.0, 6.4). Individual analyses were generally comparable to the group-level analyses.

Conclusions. Young sexual minorities are at risk for cancer through frequent exposure to cancer-related risk behaviors over time. Long-term, longitudinal studies and surveillance data are essential and warranted to track frequent engagement in the risk behaviors and cancer-related morbidity and mortality.