FAQ » Views on gender
Humans are anisogamatic—that is, our sexual reproduction involves the fusion of two gametes of different size. Persons of the female sex have a body plan centered around the production of large gametes (eggs), whereas persons of the male sex have a body plan centered around the production of small gametes (sperm).
While sex is an objective and material reality, gender is a subjective set of established societal expectations whose definitions can vary wildly from culture to culture and even person to person.
In contemporary Western society, there is a one-to-one parallel between sex and gender: unless explicitly stated otherwise, persons of the male sex are considered to be of the male gender, and likewise for female sex and gender. When a person considers themself a gender opposite their sex, they imply there are qualities about them which aren’t appropriate for someone of their sex. I assert that any person is free to have any trait, physical or personal, regardless of whether they are of the male or female sex, and that restricting that freedom stifles personal expression by reinforcing sexist stereotypes.