The long-term objectives of the proposed research are to further validate a measure of unintended pregnancy and then use that measure to explore the cultural, dyadic, and individual psychological antecedents to unintended pregnancy. More specifically, the proposed research will use a conceptual scheme and related measurement instrument, previously validated on predominantly European American, middle-class samples, to study unintended pregnancy in four racially/ethnically different, low-income samples living in Santa Clara County, California. Using Planned Parenthood clinics as a sampling resource and amplifying the sample with a snowball technique, 400 stable couples will be studied at four different reproductive stages. Three hundred of these couples will have had a recent pregnancy test and the previously developed conceptual scheme and measurement instrument for pregnancy intendedness will be tested, modified, and refined through exploratory interviews with both the male and female partners in those couples. Then, using the knowledge acquired through those explorations, all 400 couples will be interviewed with a more structured format every 6 months for 2 years with the goal of understanding and predicting four types of contraceptive behavior: contraceptive method selection, effectiveness of use, non-use, and switching. Data analysis techniques will include multinomial logit, survival analysis, and linear structural equation modeling and will be directed toward developing multivariate models of all four types of contraceptive behavior and testing those models for differences across gender, racial/ethnic group, and reproductive stage.