My understanding is that the latest research shows that the whole nature vs. nurture argument is based on a false dichotomy. That the human brain has a degree of plasticity and parts can slightly change based on environmental stimuli, and that there are parts that are "hardwired" or "preset," while others are more pliable and can adapt. If this is the case, it would suggest that even if someone doesn't have this "deformity," they're not necessarily not trans. Or perhaps this "deformity" is there but to a lesser degree. Like with research seeking to find a gay gene, I'm kind of ambivalent about it and skeptical that this sort of research will necessarily lead to a desirable outcome. Who's to say that even if they prove a difference in the brain, that this information won't be used against us? Who's to say that rather than approving HRT and SRS, insurance companies will instead seek a cheaper method of treatment to change the brain back to some falsely perceived "normal" state? Insurance companies don't want to have to provide the service you're paying them for if they can help it and will seek the cheapest option possible. Who's to say they won't just only cover the cost of some sort of "corrective" brain surgery? I can see this going in many different directions. Not to mention that if they find a way to screen babies for whether or not they'll be born trans, many people will seek abortions.
On a slightly different note, this sort of discussion always makes me think of Iain M. Banks' novels, in which the advanced civilization he writes about has the ability to change their sex at will. This is the norm in his futuristic society because it can be done so easily and can be just as easily reversed. I always wonder how many people who are not trans would change their sex for a day, week, month, or whatever, if we had such technology, just to see what it's like.
