The gender binary is a social classification system that divides gender identity and gender expression into two mutually exclusive categories (i.e., male/masculine and female/feminine) with narrowly defined limits of what is appropriate for each in terms of appearance, behavior, interests, attire, professional occupations, roles, and responsibilities. Adherence to the expectations for these categories is privileged and rewarded, whereas deviation or non-conformity results in marginalization, harassment, or discrimination.