With respect, I think you're missing the issue.
GID is not caused by any single factor. There are no causes which have been found to affect even a majority.
This is a situation which can only really be identified by its symptoms. Even then, there are so many variations in symptoms, severity and so on. Some GID sufferers are sexually attracted to those of their birth sex, others the opposite. Some say their attractions have changed after treatment other not. Some seek full treatement, others partial, others almost none. Some cope with it, some become desperate and very depressed.
Many of us report that our awareness started very young, about 4 years is quite common for those born male, a bit older for those born female. Others report their awareness came much later. Again, there is no consistance in how each of these groups experience their GID or how well they cope.
Sadly, US psychiatry seems to like tidy labels. They like to have a badge which they can pin, even when that badge is clearly preposterus.
If I lived in the US, even though I am in my mid 50s, happily married, reasonably stable and coping well with my GID, I would be subject to enforced incarceration in a mental hospital, being tied up, drugged, then enforced treatment at the discresion of some psychiatrist.
That is the issue.