CONTEXT: The extent to which young women’s risk of adolescent pregnancy is associated with having a mother who was a teenage parent, a sister who was a teenage parent or both is not known.

METHODS: A sample of 127 Latina and black adolescent females completed in-depth surveys at three time points between 1994 and 2000. Logistic regression analyses were used to examine whether socioeconomic factors, mothers’ parenting characteristics and certain sibling relationship qualities explain the association between a family history of teenage births and young women’s risk of pregnancy.

RESULTS: Compared with young women with no family history of teenage births, young women whose sister had had a teenage birth and those whose sister and mother both had had teenage births were significantly more likely to experience a teenage pregnancy (odds ratios, 4.8 and 5.1, respectively). Young women who had only a sister who had had a teenage birth had greater odds of pregnancy than young women who had only a mother who had had a teenage birth (4.5). Having both a mother and a sister who had had teenage births was independently associated with an elevated risk of pregnancy (3.7), even after controlling for socioeconomic and mothers’ parenting characteristics. Frequent companionship with an older sister was associated with increased odds of teenage pregnancy (4.5); frequent conflict with an older sister who had had a teenage birth was marginally associated with decreased odds of the outcome (0.3).

CONCLUSION: Pregnancy prevention interventions targeting young women according to maternal and sibling teenage birth histories may be effective.