I think sometimes there's a difference -- in the case where Nick actually has a learning disability, it can easily be taken to heart. In the case of my sister and I, we can call each other that and it doesn't matter. I don't know, since I don't have any kids... but I know there are a lot of parents out there who think it's okay to use those sort of words in a derogatory manner so they don't teach their kids not to. Things like "retarded" and "gay" in reference to something bad or negative really irks me. It shows intolerance.