Early on in Bem's career she created the Bem Sex-Role Inventory (BSRI), which is an inventory that acknowledges that individuals may exhibit both male and female characteristics. The BSRI is a scale developed to determine what kind of sex role an individual fulfills. It is a self-report inventory that asks participants how well 60 different attributes describe themselves by using a seven-point scale. These attributes reflect the definition of masculinity (20 questions) and femininity (20 questions), and the remaining 20 questions were merely filler questions (Bem, 1993). In this inventory the feminine and masculine items were chosen on what was culturally appropriate for males and females at that time in the early 1970s. The BSRI was later used to measure psychological flexibility and behavioral indicators. Bem also developed the gender schema theory. According to the gender schema theory, "the child learns to evaluate his or her adequacy as a person in terms of the gender schema, to match his or her preferences, attitudes, behaviors, and personal attributes against the prototypes stored within it." This theory states that an individual uses gender as a way to organize various things in a person's life into categories. Her research questioned the social beliefs and assumptions that sex roles are opposite, bipolar, and mutually exclusive. The data she collected were supportive of a merging of male and female traits to enable a person to be a fully functioning, adaptive human over an emphasis on gender stereotypes.