I’ve always said (and still mean it) that it doesn’t matter to me if and when they find some genetic or scientific explanation for why I turned out the way I am – because I KNOW who I am. But I also know that for some who struggle with the concept (whether transgender or not) that maybe if a reason was found it would help them understand or maybe even change how they feel about it.
This article was first published twenty years ago in Nature magazine. The abstract is located here and is mostly in “English”. The full article at times really gets in the weeds (and over my head) but the jist is that there appears to be a part of the brain that is “essential for sexual behaviour” in male-to-female (m-t-f) transsexuals that is noticeably more like that of a genetic female than a genetic male, and that it’s something that happens early in development in the womb. That article is here.
This picture from the article shows where all this comes from. Image A is from a heterosexual male. Image B from a genetic female. Image C is from a homosexual male (showing this part of the brain is not about sexual orientation) and image D is that from a m-t-f transsexual, and you can plainly see how much more similar it is to the genetic female that either A or C.
UPDATE: I’ve been informed of a much more recent study that affirms the difference in brain makeup in both m-t-f and f-t-m transsexuals. It too is VERY technical, but if you’re so inclined….. http://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0083947