I knew an 18 year old transsexual many years ago before he/she had gender reassignment. He was male by birth but so feminine looking that no one could tell he was not a she. Very petite and very girly looking. I lost touch for about two years and then found out that about a year after having the surgery he regretted it. He wanted to be male again. That alone gives me pause. I'm sure that there are some who would never change their minds but it does make me wonder how much of this is truly genetic and how much is psychological.