Watch the movie Idiocracy. I saw it when it came out. It's goofy, but after I saw it I feared it would come to pass in some form. Ya, that's probably gonna happen. The basis is that less intelligent / less educated people tend to breed like rabbits and generally produce offspring that are of like kind. There are, of course, exceptions to this. More intelligent people tend to breed less, if at all. Project that over time and what happens? Ooopsie.