Studies of adolescent pregnancy risk are relevant to understanding responsible adolescent sexual behavior because most investigators have focused on the key proximal determinants of pregnancy--sexual intercourse and contraceptive use--rather than analyzing pregnancy status per se. Lesser pregnancy risk is associated with teens remaining sexually abstinent, postponing onset of intercourse, and having intercourse less often or with fewer partners, as well as by using contraception at first or most recent intercourse and by using contraception consistently over time. Living with a single parent, in a lower SES family, having older sexually active siblings or pregnant/parenting teenage sisters, being a victim of sexual abuse, and residing in disorganized/dangerous neighborhoods all place teens at elevated risk of adolescent pregnancy. Parent-child closeness or connectedness, and parental supervision or regulation of children, in combination with parents values against teen intercourse (or unprotected intercourse), decrease the risk of adolescent pregnancy. Studies about parent-child sexual communication and adolescent pregnancy risk are less conclusive, largely because of methodological complexities.