Saying bad Words

I don't think that my son would ever be cursing at me or anyone that's not me. That's just really disrespectful, my son is going to grow up and have good manners and goals set for him self as a child. He won't grow up to be a bad boy or a street gangster like everyone else (no offense) to anyone that is a gangster and was brought up as one. I find it really difficult and disturbing when a two or three year old child knows bad words. It makes me feel like his or her parents didn't teach then well enough to understand what "Respect" truly is. I know for parents, sometimes not cursing is hard, but we have to get it through our adult minds that we have kids that are following after our footsteps and we are the ones responsible for setting good examples for them.