With accumulating evidence that the younger siblings of childbearing teens are at elevated risk for premature pregnancy themselves, it is both timely and important to investigate how a teen's pregnancy and parenting influence the younger siblings in the teen's family of origin. The proposed research is a 36-month longitudinal study designed to identify the psychosocial, attitudinal, and behavioral consequences of adolescent childbearing on younger siblings and how such effects may contribute to the reported early sexual involvement and elevated rate of premarital pregnancy among the younger siblings. These issues will be addressed by studying two groups of early adolescents (boys and girls, ages 11-to 13-years-old) at three points over a 3-year period: the younger siblings of pregnant teens (N=200) and the younger siblings of nulliparous (never pregnant) teens (N=200). The younger siblings of pregnant adolescents will be recruited from five city- wide sites that cumulatively serve over 3000 pregnant adolescents per year. The younger siblings of nulliparous teens will be recruited from the UCSD Adolescent Medicine Clinic. At each of the three times of assessment, subjects will complete an extensive interview and questionnaire which assess the qualities of their relationship with the older sister, their sexual attitudes, self-esteem, peer relations, deviant behaviors, future plans, pubertal status and sexual intentions and activity. Data will also be collected on subjects' parents regarding their parenting style and sexual attitudes and the older sister regarding her school performance and psychosocial functioning. A full range of statistical strategies will be used to address between group (within time) questions and within group- across time questions, such as: To what degree are the two groups of siblings differentially at-risk for low self-esteem, problem behaviors, association with deviant peers, permissive sexual intentions, and early sexual initiation?; To what extent are younger siblings' sexual attitudes and values affected by a sister's pregnancy and childbearing, and do these factors mediate the effects on sibling sexual-fertility outcomes? It is intended that the data from the proposed study will be useful in understanding the underlying processes associated with the reported early sexual involvement and premature pregnancy among the younger siblings of childbearing teens.