We grew up with it. We appropriated it for ourselves, and proclaimed it harmless. But it's not. The word "retarded" started out as a quasi-medical term—in fact, it was considered the "kind" euphemism for what came before it: things like "slow" and "dull-witted".  But it has evolved into a straight-up slur.  And when we use it, we're promoting it. March 5th is the day of awareness to end the use of the R-word. Think about it.