That's because it's a lie. With very few exceptions, people are born either male, thus having an XY chromosome, or, female thus having an XX chromosome. Rarely, a child is born with attributes of both genders, and parents have to make a decision for the child.
No amount of behavior modification, hormone therapy, or, surgery, will change the XX into an XY, or, an XY into an XX. Additionally, political correctness, activism, and public opinion will have no effect either.
These people, are mentally ill, and living a lie, and it needs to understood as such. Anyone who thinks it's normal for a grown man with a penis, and testicles to put on women's underware, a dress, and then squat on a toilet next to a six year old prepubescent little girl is right, and normal, needs help.