With studies that show brain differences, pundits and the media would have less reason to write all trans people off as nuts, as they did in the wake of the Manning press release. I saw a comparison that said, "I've decided I'm a chair, and now everyone will have to refer to me as a chair." Response: "Well, actually, it's a structural brain difference." Then they are in a position where they are denying science.
That is not to say righteous ignorance won't persist even with clear cut evidence.
But at least the general educated public would see them for what they are instead of quietly agreeing with them in the back of their mind, which is what I am pretty sure happens now.
"I have an intersex brain condition, so please refer to me with male pronouns.." is way easier to process than even, "I was born in the wrong body." There seems to be many trans people that want nothing to do with the GLB spectrum, and stuff like this really highlights the key differences and why the T doesn't always belong with the GLB for some.