Gender in general is an outdated concept whenever we're past all the bullshit about how much influence your genitalia or chromosomes have over your capabilities or worth as a person. In Japan, possibly other parts of East Asia, blood type is considered to be a key factor determining your personality. Obviously that's nonsense scientifically. Same with horoscopes in the West. Your birthdate doesn't affect your daily life.

Outside of reproductive functions and certain logistical concerns of having sex, we'd all be better off if we didn't think so much about sexes or genders. Having a vagina shouldn't influence the appropriateness of wearing baggy cargo shorts. Having a penis shouldn't disqualify you from a professional career in childcare. Comments on sexuality or physical attractiveness of coworkers need to be totally off-limits in the workplace.