Gender is the range of social, psychological, cultural, and behavioral aspects of being a man (or boy), woman (or girl), or third gender. Although gender often corresponds to sex, a transgender person may identify with a gender other than their sex assigned at birth. Most cultures use a gender binary, in which gender is divided into two categories, and people are considered part of one or the other; those who are outside these groups may fall under the umbrella term non-binary. Some societies have third genders (and fourth genders, etc.) such as the hijras of South Asia and two-spirit persons native to North America. Most scholars agree that gender is a central characteristic for social organization; this may include social constructs (i.e. gender roles) as well as gender expression.
The word has been used as a synonym for sex, and the balance between these usages has shifted over time. In the mid-20th century, a terminological distinction in modern English (known as the sex and gender distinction) between biological sex and gender began to develop in the academic areas of psychology, sociology, sexology, and feminism. Before the mid-20th century, it was uncommon to use the word gender to refer to anything but grammatical categories. In the West, in the 1970s, feminist theory embraced the concept of a distinction between biological sex and the social construct of gender. The distinction between gender and sex is made by most contemporary social scientists in Western countries, behavioral scientists and biologists, many legal systems and government bodies, and intergovernmental agencies such as the WHO. The experiences of intersex people also testify to the complexity of sex and gender; female, male, and other gender identities are experienced across the many divergences of sexual difference.
