The reason why some people are stuck on two genders is inertia, in some part religious based inertia.
Nope, it's science and biology.
That is redundant. And likely incorrect. After all, geocentrism was supported by
science and astronomy.
But thanks for doing your typical slice and dice and then leave a shit in the thread routine.
There are only two sexes in humans. There are only two sexes in all mammals, all birds, the overwhelming majority of vertebrates, and a sizable portion of plants.
Gender, on the other hand, is simply the way in which a person likes to express themself as it relates to the prevailing sex-based stereotypes of their culture. There's bazillions of ways for that to happen, and I support everyone's right to engage in them to their heart's content... but it doesn't change one's sex. Their sex stays what it was since about the 7th week of gestation, even if the exterior is manipulated to mimic the opposite sex extremely well.
Neither one's sex nor one's presentation and behavior should preclude a person from owning a home, renting a jet ski, ordering a steak, or studying a subject, or any number of other commonplace scenarios we can imagine. In most of the ways we interact in society neither of those are pertinent - They're irrelevant, and should be irrelevant in those situations!
But even so, there are some situations where one or the other of them actually
do matter. A person's preferences and desires around how they wish to dress, or to present themselves, or to express themselves certainly matters when they're shopping and purchasing items related to those presentations - clothing, or jewelry, make-up, accessories, or all sorts of other things. There are probably other scenarios where they matter too.
There are some spaces and services where sex matters. And in those spaces and services, they happen to matter a whole lot more for women than for men. In spaces where we're naked or particularly vulnerable, it actually matters a lot that we're females, but it doesn't matter one bit if we like short hair and steel-toed boots. How "butch" we look is of little import when your vulnerability to a sexual assault is heightened. If you're in prison, or are confined somewhere you can't reasonably leave like a hospital bed, it can matter a lot if the person in the bed right next to you while you sleep is male... but it doesn't make any difference how you present. In athletics, the normal distribution of ability and strength of your opponents is what makes the competition fair and meaningful, so when the person across from you falls well outside the standard deviation of the abilities of similarly skilled competitors, that has a big impact.
I don't believe that a person's internal identity as it relates to their preferences around presentation should take precedence over the realities of sex
in spaces and services where sex matters.