Trans people's gender is no less 'natural' than cis people's gender identity. If you have to use the power of the state to coerce people into conforming to gender norms, you are making a loud admission that you do not, in fact, believe that assigned gender is a fact of nature.
I've never understood this obsession with "natural" limits on human behavior. As though anything we do in modern society could be viewed as remotely natural. Like what about your Tesla and iPhone is natural? Such strange reasoning.
I've started making conservative people uncomfortable by saying it's silly how people are so obsessed with other people's genitals and why can't we all just mind our own business. They visibly squirm when they realize it's them. They're the asshole.
I can't remember the book's title at the moment, but it was a real head-scratcher for me when I learned that even the discourse of "biology" as we call it is created by human intelligence and isn't natural per se. the gender binary is a product of this discourse and not just found by human beings