Abstract
INTRODUCTION: Sexual minority girls (SMGs) may be at high risk for substance use partially due to anti-gay discrimination. Low levels of parent-child communication and parental knowledge may contribute to this risk. This study seeks to identify parent-child communication and parental knowledge trajectories, determine the likelihood of SMGs following these trajectories, and describe the relationships between these trajectories, sexual orientation, and substance use. METHODS: This is a secondary data analysis of the Pittsburgh Girls Study (N = 2450), a longitudinal study on the changes in behaviors among girls throughout childhood. We generated group trajectory models of parentchild communication and parental knowledge starting from age 12 to age 17 years. We then tested the likelihood of SMGs belonging to these group trajectories and the association between group trajectory membership and substance use at age 18 years. RESULTS: SMGs were more likely than were heterosexual girls to follow the infrequent decreasing parent-child communication trajectory and the slowly decreasing parental knowledge trajectory and were more likely than were heterosexual girls to engage in substance use at age 18 years. Parent-child communication and parental knowledge trajectories were statistically significant mediators between sexual orientation and substance use. CONCLUSION: Frequency of parent-child communication and levels of parental knowledge may be determinants of substance use among SMGs. These results have implications for developing substance use prevention programs among sexual minority youth targeting parent-child relationships.