Various definitions of gender identity have ranged from recognition of one's biological sex to an individual's sense of masculinity or femininity. For the purpose of this paper, which examines some of the theoretical approaches to the subject, gender identity will be defined as "the degree to which individuals are 'aware' of and accept their biological sex." Psychoanalytic or identification theories emphasize individual personality development, while social structural theories examine the way in which society creates and supports gender roles. Evolutionary theories have stressed possible genetic and functional bases for behavioral differences between the sexes. Other theories focus on "how" gender differences occur, rather than "why" they occur. Social learning theory proposes that both gender identity and gender role are learned through a process including observation, imitation, punishment, and reinforcement. Cognitive developmental theory proposes that the concept of gender cannot be learned until the child reaches a certain stage of development. Gender schema theory proposes that individuals with strongly developed gender schemas will spontaneously sort information into categories based on gender. Social interaction theories are concerned with the processes that maintain continuity of gender-related behavior and that elicit such behaviors in specific social contexts. Contains 37 references. (BF)