A surprising number of “studies” that links are posted for are actually not studies at all, but proposals the author argues are worthy of research. Below is a link to such a proposal. I will post others under this category.
The author argues that “the fetal brain develops during the intrauterine period in the male direction through a direct action of testosterone on the developing nerve cells, or in the female direction through the absence of this hormone surge. In this way, our gender identity (the conviction of belonging to the male or female gender) and sexual orientation are programmed or organized into our brain structures when we are still in the womb.
However, since sexual differentiation of the genitals takes place in the first two months of pregnancy and sexual differentiation of the brain starts in the second half of pregnancy, these two processes can be influenced independently, which may result in extreme cases in trans-sexuality.”
However this is simply a theory. The author has published this paper outlining some proposed research to examine whether there is any evidence to back up this theory. So until some research actually takes place, this citation is totally meaningless.