This is one of the funniest movies of all time, because it feels like it could really happen. But it's not for kids. There is some cursing (but not as much as many other films with the same rating), and sexual things are discussed and implied (but fortunately never shown on screen). It's just some dark humor about stupid people. We've all thought deep down at some point that the "wrong" people are having all the kids. This takes that premise and runs with it; all of the educated people are putting off having kids sometimes until it's too late, and the trailer trash breed like rabbits, resulting in a collapsed society where no one knows how to deal with basic problems anymore. It's kind of related to a science fiction work called "The Marching Morons."
Again, I wouldn't show it to kids, but your adult friends will think this is hilarious while at the same time fearing for humanity.