A sex change operation is not "merely" plastic surgery. After a male or female has been so mutilated, they can no longer function as male or female. This mutilation results in a loss of natural function.
And the gaining of other function. Well, at least in MtF - FtM isn't as developed.
From what you said earlier:
or enable the patient to function normally.The patient WANTS to function as the other sex.
You call it 'mutilation', true. Personally, I'd call it mutilation myself if I was so operated on. But it's
their choice. Like the epileptic, they could just learn to live with the disconnect.
Your word games are less than impressive.
The problem is, I've moved beyond 'word games', posting things like studies. You're the one who is depending on nothing but word games.
I'll go back to what I've said, supported by scientific study: There are actually people out there who's brains make them want to be the opposite sex, most likely due to complicated things involving prenatal hormone levels at various points during the pregnancy. Their mental view is different than their physical body.
Now, this is a problem. Choices I can think of are:
1. Suck up the problem. Hello suicide rates, unhappiness, etc...
2. Change their body - physical surgery.
3. Change their mind - At this point mucking around with the firmware is a much less developed science than mucking with the hardware.