Of current sexually active high school students, 13.7% report not using any methods to prevent pregnancy (1). Girls and young women are more likely to report unprotected sex than their male counterparts (15.7 vs. 11.5%) and the consequences of such risky sexual behavior are also greater in girls and women including profoundly elevated risks for unintended pregnancy and exposure to sexually transmitted infections. Substance use, during the lifetime as well as immediately preceding sexual intercourse, has been frequently implicated as an independent contributor to likelihood of such risky sexual behavior, including, early sexual debut, having multiple sexual partners and repeated voluntary unprotected sex (rVUS)(2-5). Use of cannabis, particularly during adolescence, has been cross-sectionally and prospectively linked to risky sexual behavior (6-11). However, no study to date has used a genetically informed design to disentangle the role of person-specific factors that may be of a causal nature from the contribution of common predisposing factors that might influence both adolescent cannabis use and rVUS.
