Preventing adolescent pregnancy: biological, social, cultural, and political influences on age at first sexual intercourse.

Age at first sexual intercourse (AFSI) is the initial factor related to adolescents' sexual life that may increase the risk of adolescent pregnancy. We explored the biological, social, cultural, and political predictors of AFSI addressing several gaps that prevent us from generalizing the results of past research to adolescent pregnancy prevention. We also explored the moderating effects of cultural variables on the links between social and political predictors and AFSI. Our sample consisted of 889 Portuguese female adolescents aged 12-19. Earlier age at menarche, non-intact family structure, maternal history of adolescent pregnancy, lower maternal emotional warmth, absence of religious involvement, and living in Portugal's mainland and in a legal context penalizing abortion predicted earlier AFSI. School attendance predicted earlier AFSI among adolescents of European ethnic origin; adolescents of non-European ethnic origin presented the opposite, but non-significant, pattern. These findings suggest that, in addition to isolated characteristics, factors from different ecological contexts should be considered when planning interventions designed to foster healthy and informed transitions to sexual initiation and prevent the related risks of unwanted outcomes. We discuss implications for future research and practice.