Gender is not something we have but is something we do. Gender is the behaviours a society expects of people based on perceptions of their biological characteristics, and so gender is something we learn to perform – how to move, how to dress, how to speak, how to relate to other people based on our perceptions of their gender. In the dominant culture in North America, gender is divided into two categories: male and female. This is called the gender binary, and almost all people are assigned to one of these two categories at birth. Our internal sense of gender – our gender identity – however, might or might not fit with our gender assignment. People whose sense of gender identity fits more or less well with their gender assignment are denoted cisgender. People whose sense of gender identity does not fit with their gender assignment are transgender, gender non-binary, gender non-conforming or any of a number of other gender identities.

The gender binary plays an important role in reinforcing sexism, the system of oppression that maintains a hierarchy with men over women. This hierarchical structure is known as patriarchy. This system is pervasive, affecting and supported by social institutions like government, education, media, health-care, family and religion. The gender arrangements of patriarchy, the ways in which beliefs, relationships and institutions force people into patterns of behaviour, compel patterns of constraint, discrimination and oppression that appear in many Christian institutions in North America as limitations on women's religious leadership, restrictions on women's control of their own sexuality and fertility, gender violence, and condemnation of transgender and gender non-binary people. It also limits the scope of acceptable masculinities, boxing men into stereotypical roles of patriarchal authority and dominance. These arrangements also reinforce and are reinforced by heteronormativity, the assumption that everyone is heterosexual and the social practices that underpin this assumption (forms that ask for mother and father, wedding paraphernalia for bride and groom, etc.) and heterosexism, the system of oppression that maintains heterosexual dominance through norms, laws, policies and practices (such as excluding LGBT people from ordination or, until recently, from marriage).

People, however, do not simply go along with their oppression; they also resist. Feminism is, as feminist scholar bell hooks puts it, a movement to end sexist oppression.