Examines the associations between family and individual characteristics and having a first sexual experience before age 16 with an older partner, and between age and partners’ age difference at first sex and contraceptive use and having or fathering a child as a teenager. Concludes that interventions should target specific teenage populations, including males, to dissuade them from having sex at a young age and with older partners. Also, prevention efforts should target potential older teenage partners and adult partners of young teenagers.