Is there any good non "grievance studies" literature on gender disorders and transsexuals?

Google only shows up PC bullshit and ddg is a mess to search on.

Pretty much all smart people and psychologists I've talked too seem to agree that changing sex is mental but I'd like too see concrete data.

There's also the 40% suicide rate and the trans regret but I can't find the papers on that.

Also general discussion about the topic, please keep it more on /Sci and less on /pol