Reviews the literature to identify the most important antecedents associated with adolescent initiation of sex, contraception use, and pregnancy. Results indicate that over 100 antecedents create a complex, detailed picture of the correlates of adolescent sexual behaviors. They describe characteristics of adolescents themselves, their partners, peers, families, schools, and communities, and relationships to these entities. They include antecedents that are inherently sexual and nonsexual. (SM)