Gender

Gender was a set of social groups used by humans to define themselves. Humans had certain stereotypes associated with at least some genders. (TV: World Enough and Time)

Examples of genders included male, female (TV: Extremis), exposition, and comic relief (TV: World Enough and Time), although it was a "spectrum" and there were many more. (PROSE: Island of Death)

Time Lords had moved beyond human concepts of gender by the time the Doctor was a child. (TV: World Enough and Time)