Gender

Latin genus — kind, type, birth. Related to generare — to generate. In grammar, gender referred to noun categories — masculine, feminine, neuter — not to human biology. The word's application to human identity is relatively recent.

Sex and gender were used interchangeably until the 1950s-60s when researchers began distinguishing biological sex from social identity. That distinction is now the fault line of one of the most intense political conflicts of the 21st century — a debate that is ultimately about who has the authority to define categories.