Initiation of sexual intercourse among middle school adolescents: the influence of psychosocial factors.

PURPOSE To explore potential psychosocial predictors for initiation of sexual intercourse among middle-school, inner-city youth, using longitudinal data from the Healthy and Alive! project. METHODS We conducted hierarchical, logistic regression with adjustment for intraclass correlation over two sequential periods, including seventh and eighth grades (N = 3163), to assess the independent influence of psychosocial and demographic factors. Internally reliable scales to assess psychosocial influences were created, based on major theories of behavior. The sample was 52% female, 51% black, 30% Hispanic, 9% white, and 3% Asian. At baseline, 13% of girls and 39% of boys reported already having initiated sexual intercourse. RESULTS Personal and perceived peer norms about refraining from sex were a strong and consistent protective factor. Alcohol and other drug use, poor academic performance, male gender, and black race were consistent risk factors. Self-efficacy showed a mixed effect: protective in the seventh grade but increasing risk in the eighth grade. Speaking a language other than English was a protective factor in seventh grade. Both psychosocial and demographic factors provided independent explanatory power. CONCLUSIONS Psychosocial factors, particularly norms about having sex, influence initiation of sexual intercourse. These data suggest that programs to delay initiation of sexual intercourse should reinforce norms about refraining from sex.