The gender binary (also known as gender binarism) is the classification of gender into two distinct, opposite forms of masculine and feminine, whether by social system, cultural belief, or both simultaneously. Most cultures use a gender binary, having two genders (boys/men and girls/women). In this binary model, gender and sexuality may be assumed by default to align with one's genetic or gamete-based sex, i.e. one's sex assigned at birth. This may include certain expectations of how one dresses themselves, their behavior, sexual orientation, names or pronouns, which restroom they use, and other qualities. For example, when a male is born, gender binarism may assume that the male will be masculine in appearance, have masculine character traits and behaviors, as well as having a heterosexual attraction to females. These expectations may reinforce negative attitudes, biases, and discrimination towards people who display expressions of gender variance or nonconformity or those whose gender identity is incongruent with their birth sex. General aspects The term gender binary describes the system in which a society allocates its members into one of two sets of gender roles, gender identities, and attributes based on the type of genitalia they have. In the case of intersex people, those with rare genetic abnormalities which give them the sex organs of both sexes may have difficulties fitting into this system. Scholars who study the gender binary from an intersectional feminist and critical race theory perspective argue that during the process of European colonization of the U.S., a binary system of gender was enforced as a means of protecting patriarchal norms and upholding European nationalism. Traditional gender roles are influenced by the media, religion, mainstream education, political systems, cultural systems, and social systems. Major religions such as Islam and Christianity, in particular, act as authorities for gender roles. Islam, for example, teaches that mothers are the primary care givers to their children. The Catholic Church, the largest Christian denomination, only ordains cisgender men as priests. Christianity supports its adherence to a gender binary with the Book of Genesis in the Bible, where it is declared in verse 27 that "God created man in His own image; in the image of God He created him; male and female He created them." Orthodox Judaism also forbids women to be ordained as rabbis and serve as clergy in their congregations. In English, some nouns (e.g., boy), honorific titles (e.g., Miss), occupational titles (e.g., actress),