here are many disorders that cannot be explained or seen, how can you be so sure that transgender people are not suffering from a hidden malfunction at birth of being born with the mismatched reproductive organs and chromosomes?
Transgenderism as it presents itself today, is a modern creation.
The rate of transgendered people increases with its publicity & its promotion.
You may, also, as well ask are gay people suffering from 'malfunctions' - since at one end of the life span it is mainly young gay men and women who are transitioning.
The rate of older, male transvestites transitioning into full time 'womanly pursuit' is also on the increase - as transgenderism and transitioning becomes a contemporary 'thing' - and with the explosion on trans, and other types, of pornography.
Modern medicine and surgical technique have also fuelled a demand for body modification in response to personal feelings of discomfort, anxiety, dysmorphia, fetish etc. A whole industry, and professional careers, have been built around this post-modern ideology, funded by people such as J.Pritzker, and other prominent, and wealthy, transvestites and gay men.
The fact that the desistance rate is so high - and that many/most young people eventually do desist, puts paid to the idea that there is some biological imperative - and points to the fact that 'transgenderism' is actually a social construct.
I'm sure many billions of American dollars are being poured into finding some biological link, though. Seek and ye shall find.