Can a prevention program that never discussed sex or contraception with its participants reduce rates of early age intercourse among adolescents? The current study examined whether a parenting intervention designed to prevent youth mental health disorders and school dropout could also have 'unanticipated' effects on early age intercourse. The sample consisted of 516 Mexican-origin adolescents and their mothers who participated in a randomized intervention trial which aimed to change parenting practices. A series of path models were examined in which two parenting practices, harsh discipline and supportive parenting, were hypothesized to mediate the effects of the intervention on adolescent early age intercourse.

Results indicated that the intervention successfully reduced maternal harsh discipline in the experimental group versus the control group. In turn, post-intervention levels of harsh discipline predicted higher rates of early age intercourse. Tests of mediation provided further evidence to support these pathways, and subsequent invariance tests revealed that the significant mediated effect among the intervention, harsh discipline, and early age intercourse was moderated by youth gender. Surprisingly, this mediated path only held for boys and not girls. In contrast, no mediation effects were found with supportive parenting. Findings support the central hypothesis that an intervention that does not discuss sex or contraception can impact early age intercourse through changing parental harsh discipline. Given the controversial nature of abstinence and sex education programs, studies such as these may provide an alternative approach to preventing early-age risky sexual behaviors that may be palatable to broader segments of the population.