This study addresses the development of young children's sex identity and knowledge of culturally prescribed sex roles, and the process by which maternal childrearing behaviors contribute to this development. Previous research has demonstrated that by the time children are 5-6 years of age, consistent sex differences appear in children's choices of activities, their motives when engaged in an activity, and their performance styles. There are few detailed data on factors contributing to these differences. The goal of this study is to fill this gap. Maternal behaviors with girls and boys are being observed over a range of activities. This study is a by-product of the laboratory's Rearing Study which provides extensive interactional data on 100 mothers and their children, and thereby permits a focus on sex of child as a determinant of rearing environment. The data sources are videotaped observations of mothers and their 2-3 1/2-year-old children in a variety of naturalistic settings. Similar observations are obtained two years later. In the follow-up observations, a series of gender related probes have been incorporated which will provide information about the mother's conscious preferences for her child as well as the child's own preferences for her/himself and knowledge of the cultural sex stereotypes.