I've said it before, too: I'm guardian of an adult who suffered significant brain damage as a child and is functionally about 12. He's not retarded...he's literally brain-damaged, and developmentally disabled. But not retarded. And my uncle with Down's passed a few weeks ago - he had a genetic condition, but again...not retarded.
The only retarded people I know are the ones who say "You don't know what it's like to be around kids with special needs, if you call them retarded." Yeah...I do know what it's like, and I don't call them retarded, because they're not retarded, they're "special needs." I call the retards who say that retarded.