To all those with a fixation on the use of the word "retard" in the film "Tropic Thunder," I have one question: Where were you when the Pixar film "Monsters, Inc." was released? That children's movie used the word "cretin" a word which, until the middle of the 20th century, was a scientific term for what we now call "mental retardation." That term is slowly getting phased out. The same goes for "idiot," "imbecile" and "moron." These used to be more than just insults, they were terms for specific ranges of mental retardation, used in old scientific journals and still part of the law in several states.
My point is that while the word "retard" is hurtful to some, its modern usage is a result of a natural linguistic shift that has happened several times before.
Salt Lake City