Thanks for the replies.
The reason I was curious, though, was because I saw some virulently transphobic claptrap and started pushing back against it, only to realize that it'd be handy if I actually knew what I was talking about. I figured that there's talk therapy before anything medical happens, and was curious where I could find out more about that. Well before the medical interventions that transphobes keep fixating on.
Edit:
This, largely. Again, my curiosity comes from a place of wanting to be informed when I tell transphobes just how wrong they are.