Gender defines individuals throughout their lives in multiple ways. This entry reviews the impact of gender on people’s identities, attitudes, temperament and adjustment, sports participation and play, academic achievement and occupations, relationships and family roles, and prosocial and aggressive behavior. Gender-related variations in these areas may be affected by a combination of biological, motivational, interpersonal, and [Page 922]cultural factors. Also, for most of these outcomes, there is usually a high degree of overlap between females and males whereby similarities may be more common than differences.