Those who doubt that people can be trans or that nonbinary people exist are on the same level of ignorant as a pre-archimedian mathematician believing that no numbers exist other than positive integers, negative integers and null.
Get with the times, you have rational genders, irrational genders, transcendent genders, hyperreal genders, surreal genders, p-adic genders, and best of all, genders that lie on the complex plane.