How can a comment about gender be a true biological fact? Aren't you mixing up sex and gender?
So even "there are only two biological sexes" -- while less untrue than "there are only two genders" -- is apparently not an entirely 100% "true biological fact".
sex: male / female. you're born with. other : ? gender : male / female. what you feel being. other : a teapot ? you're insane.
the type or person of what's people are attracted with : i don't give a f it does not matter.
As for gender it's a social construct so using a binary qualification makes no sense. One could say it's a spectrum but it doesn't even have to be this restrictive. Why force people to take the whole package of constructs and ethos from either one? What's wrong with having a beard and makeup? Is this insanity to you?
Of course this is not about identifying as object. Please don't use mediocre rhetoric like that.