Historically, the terms gender and sex have been used inter- changeably. Because of this, gender is often viewed as a binary—a person is either male or female—and it is assumed that a person’s gender matches their biological sex. This is not always the case, however, and more recent research has separated these two terms. While the majority of people do identify with the gender that matches their biological sex (cisgender), an estimated 0.6% of the population identify with a gender that does not match their biological sex (trans- gender) (Flores et al., 2016). For example, an individual who is biologically male may identify as female, or vice versa.
In addition to separating gender and sex, recent research has also begun to conceptualize gender in ways beyond the gender binary. Genderqueer and gender nonbinary are umbrella terms used to describe a wide range of individuals who do not identify with and/or conform to the gender binary. These terms encompass a variety of more specific labels individuals may use to describe themselves. Some common labels are genderfluid, agender, and bigender. An individual who is genderfluid may identify as male, female, both, or neither at different times and in different circumstances. An individual who is agender may have no gender or describe themselves as having a neutral gender, while bigender individuals identify as two genders.
It is important to remember that sex and gender do not always match and that gender is not always binary; however, a large majority of prior research examining gender has not made these distinctions. Thus, the following sections will discuss gender as a binary.