When IS it appropriate to say "retarded"? I noticed some of you mentioned it was okay if referring to a dx, but would never use that as a term to define an individual's disability/handicap. If someone had a handicap, I would refer directly to that issue (ie, "My cousin has Down's Syndrome" or "My uncle was born with hydrocephalus") instead of saying they were mentally retarded. The only time I have ever seen it used that didn't offend me was in scientific journals that were referring to retarded growth patterns (in plants or whatever) related to various experiments.
I don't know if I am necessarily politically correct either, though.