I mean, science is a framework that can be applied to anything. Sociology included. So we can't currently measure a genetic cause for trans. I guess that means our current best measurement is what gender people associate with, what they personally feel is right. That also happens to be the best path towards not being a dick to people who feel like their gender does not match their "biological" gender.

If and when we can improve our measurements of this maybe we'll learn something new. Maybe we can learn what components of nature and nurture lead to gender disphoria. Then we can try to further improve quality of life for affected folks.