Previous research indicates that children of adolescent mothers are more likely to experience an adolescent birth than are children of older mothers. Using a longitudinal sample of 293 high-risk mothers and their 19-year-old children, we investigated mediators of the intergenerational pattern of adolescent childbearing. Results from multigroup path models indicate that the intergenerational effect is (a) significant for children of unmarried mothers above and beyond mother's prebirth socioeconomic status and education level, (b) fully mediated through early sexual intercourse related to presence of a father figure and early home environment for girls, and (c) partially mediated by early physical development for boys. Relation of findings to current models of early sexual behavior and childbearing is discussed.