Here's my convenient list, from my blog, of just some of the scientific peer reviewed papers that demonstrate hormonal in utero links to why we are trans.
One Stop Trans Brain Research ListIn addition, I've not yet linked it there, but I also recently read about a study in genetics that show there are two genes that can regulate how testosterone receptors behave and the longer receptors (a recessive gene) processes testosterone less efficiently. So... if a mother has initial issues with hormonal levels in utero between the 8th and 24th week of pregnancy (especially between the 8th and 16th week), and if the child has the recessive gene for less efficient androgen receptors, then that child might have a heightened chance of turning out trans.
Critical things to remember.
1 in 30,000 females at birth is XY. Most are sterile but rarely some are not, can conceive and give birth. (See link:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2190741/ )
1 in 25,000 males at birth is XX (de la Chapelle syndrome). They grow as little boys and never think of themselves as anything other than male usually.
Klinefelter's babies are XXY and were long thought to be exclusively male but that's not true. What happened was XXY males had medical complications so were seeking out medical treatment. XXY females generally don't have medical complications so weren't seeking out doctors, but now that biologists know they are out there, they are looking for them.
Medically, the NCAA and the IOC both consider MTF as women once they've been on hormone replacement therapy for two plus years. In addition there is a wealth of medical evidence showing trans women not only do not have an advantage against cisgender women but may actually have a disadvantage because of lower natural testosterone levels.
Medical Information about Transwomen in SportsThen there is this little gem (from one of the studies I linked on another of my blog entries):
Why Transition is the Overwhelming Treatment of ChoiceAs to why it can take so long, consider what I went through when young:
1. parental and grandparental shock and horror at expressing myself
2. physical violence directed at me by other kids
and encouraged by adults because i was a "sissy"3. constant reminders that anyone not completely straight and "normal" was "queer" and automatically labeled a pervert, an abomination, and a monster
4. friends who were "queer" experiencing even more ostracism and violence than I did.
Now what kind of message do you think a child in that situation might be receiving?
And finally, sometimes dysphoria manifests in other was, trying to get our attention. Zinnia Jones wrote about that so look at your own life. Did you do things that weren't "normal" to "escape" from yourself? OCD behaviors? Generalized obsessions? Undefined depressions?
"That was dysphoria?" 8 signs and symptoms of indirect gender dysphoriaThe whole situation is really, really complicated but I hope these links provide a little bit of insight into some aspects of that complicated topic. I know that these links have helped me personally.