We have an increasing amount of evidence that being trans has some physical biological component. Here's a fresh article on the subject https://www.gilmorehealth.com/augusta-university-gender-dysphoria-in-transsexual-people-has-biological-basis/#The_biological_basis_of_sexual_dysphoria

I've also seen a shortish talk from a researcher in the field who said there have been instances of neurological evidence, too. I don't remember the details, and I can't find the specific talk without remembering them, so I unfortunately can't cite it and will have to speak a little more generally, but they found structures in the brain that corresponded to their chosen gender, NOT their assigned at birth gender.

So we do actually have some evidence for "wrong bodies" if that's how you wanna phrase it.