Talk politics.

Ah, yes, but this is the great epithet arms race, isn't it? At one point, "mentally retarded" WAS the politically correct term. Until people started using it as an insult. Same with "spastic", "idiot", "moron", "stupid", "imbecile." This happens because people WITH these disabilities are looked down upon. No matter what we call them, that term will end up as an insult, simply because of how people feel about people with disabilities - to compare an able-bodied individual to someone with a disability is considered an insult. Until you correct that attitude and make society more egalitarian, you will never have a "PC" term for long. It will always end up as an insult, and then you'll need a new word... again and again and again.