Reported are findings from the first phase of a longitudinal study concerning the impact of the first year of school on the development of young children's social gender identities. Ethnographic research in two primary schools in the south of England identified six aspects of settings which can be used to mark gender: social categories, group composition, space, material culture, activities, and behavioral styles. Of the six, grouping, space, and materials are discussed. Longitudinal observations were made in three first-year classes of the schools. Observations conducted over a period of weeks in the second half of the first school term resulted in the recording of target children's activities. At least 10 and no more than 20 observations were recorded for each child. Findings identified the resources for the expression of social gender identities that are available to children as they enter school. The resources marked as masculine and feminine can be mobilized by children who are entering school. (RH)