Holly wrote:And why are there so many more M2F trans than the other way around?
The science on that is uncertain but here is what is held the most likely theory.
In the early stages of development all embryos are the same and, if certain bio-chemical triggers don't go off - will become girls as the continue to gestate. Roughly 50% of embryos should be pre-programmed to become male at some point but those triggers don't always operate and the child develops into a normal girl.
Some of the triggers change the way the body develops and some change the way the brain and cognitive processes develop and they don't go off at the same time.
The current theory is that usually the body change trigger goes off first and, once detected, brain and cognitive process changes follow as the 'maleness' - for want of a better word - comes through.
When the body change trigger happens and the other triggers fail you get a person who is still - in their brain and in terms of cognitive processing - a woman. And studies have found trans-women's brains react more like women's brains than like men's and this can cause real problems, a body - and particularly one part of the body -is pumping in hormones that the brain simply can't deal with.
It's far less likely that the cognitive processes will change to male if the body change trigger hasn't gone off first.
That's from a lot of bio-chemistry and biology that I don't really understand that was explained to me slowly and patiently when I asked why there are more girls born than boys even when those who selectively terminate pregnancies tend to terminate girls more than boys.
For what it's worth that's a best guess.
And I agree that anyone who has been through male puberty - whether natural or similuated as the USSR used to do with some of its female athletes, should not compete in women's sports