There is a particular kind of mental illness that makes people want to discard a limb, no matter how painful the amputation is. There are some physicians willing to do the amputation, as long as they are paid. And then, there are those who want their genitals mutilated.
It is indicative of how far medical science has to go, that we do not know how to cure these people without mutilation.
If we can’t cure them, for G-d’s sake we can at least medicate them.