The gender binary refers to the concept of there being only two genders. It is also frequently thought about in terms of masculine/man versus feminine/woman. The gender binary is not inclusive of gender identities that do not fall into this polarization of masculine or feminine identities. The gender binary also forces those who do identify as men or women into strict gender roles. If one does not follow these rules set by the gender binary, they will face repercussions dependent on the transgression and the cultural context.
Killerman, S. (n.d.). The Safe Zone Project: Core Vocabulary. Retrieved October 13, 2020, from https://thesafezoneproject.com/activities/core-vocabulary/