Gender is a thing, gender roles are not. If gender wasn't a thing, transgender people would be transgender because of psychological or societal reasons. That's not the case, they're born transgender, and no one can "become" trans, just like no one can "become" gay, just like no one can become left handed.

This kind of thinking is actually transphobic as fuck because basically it's implying trans people are trans because they want to. And no one would want to be trans. It's horrible, you're born in the wrong body, surgery is hard, and hormone therapy takes a lot of time. And once SRS is done, there is still discrimination, and sometimes even family members won't accept you. Trans people aren't just people with a weird kink like TERFs believe, they're not just people that mildly enjoy for some reason wearing clothes of the opposite gender. They are for real. It's not a phase.