It isn't that it is wrong, it is that it is not possible.
It is a symptom of a mental illness.
No one has suggested outlawing crossdressing.
But the many wishing to outlaw the use of body modification and hormonal medications for children are justified in that it does not cure the mental illness and that the survivors later come to accept that they are simply homosexual.
And no one, the public, the insurance companies, even the affected individuals, wants to pay for it.