Actually, retard has just been a shortening of the accepted clinincal term. Retardation has been used for quite some time, and has about as much legitimacy as dunce. As Swamp mentioned, it's all about context.

Now I don't want anyone claiming that I support going around calling people "retards", I'm just growing weary of people vilifying the word. As I mentioned in my first post in this thread, moron and idiot were once commonly used professional terms as well, it's just that as the public becomes aware of them, they are often twisted to be used as insults. Frankly, I don't think it matters what words are used, people will continue to insult each other all the same. And they'll do so un-impeded by society, because society is busy arguing over which particular word is being used.

MV