Predicting the timing of first sexual intercourse for at-risk adolescent males.

Event history analysis was used to test a developmental model of the timing of first sexual intercourse in the Oregon Youth Study sample of adolescent males at risk for delinquency. The event history models spanned grades 7-12 with yearly multimethod, multiagent measures. A 3-step mediational model of predictors was tested, including contextual and process factors and boys' characteristics. Predictors included one-time measures of socioeconomic status, parental antisocial behavior, and time-varying measures of parental transitions, parental monitoring, deviant peer association, and the boys' antisocial/delinquent behavior, substance use, physical maturation, academic achievement, and anxiety. As predicted, antisocial/delinquent behavior and substance use along with early physical maturity and parental transitions predicted early onset of sexual intercourse. Anxiety was related to delay of first intercourse. Results and intervention implications are discussed in terms of the developmental findings.