CONTEXT: Sex at a young age with an older partner has been linked to poor reproductive health outcomes during adolescence, but minimal research has examined the influence of teenagers’ having an older sexual partner on reproductive health outcomes during the transition to young adulthood.

METHODS: Logistic regression and contrast analyses of three waves of data from the National Longitudinal Study of Adolescent Health were used to examine whether individuals who had had sex before age 16 with a partner at least three years their senior were at increased risk of becoming teenage or unmarried parents or of contracting an STD by young adulthood.

RESULTS: Ten percent of females and 2% of males had had early sex with an older partner. These females were more likely to acquire an STD as young adults than were those whose riskiest relationship was before age 16 with a similar-aged partner (odds ratio, 2.1) or at age 16 or later with a similar-aged or older partner (2.4 and 2.6, respectively). For males, having sex before 16, regardless of partner age, was associated with an elevated STD risk (odds ratio, 1.9), although controlling for relationship history characteristics attenuated the association.

CONCLUSIONS: Adolescents, particularly young adolescents, should be made aware of the potential risks associated with having older sexual partners. In particular, program providers should be alerted that females who engage in early sexual activity with older partners are at especially high risk of experiencing adverse reproductive health consequences.