Chipman DNA is pretty bad in itself, and when combined with Sarah's DNA the results were never going to be great. No child progedies are ever going to come out of the Chipman family line. If I've ever seen a family that genetics has designed to be dull-normal manual laborers, it's the Chipmans. One hundred years ago, Bob and Chris would have worked repetitive, physical tasks ten hours a day, and I bet they both would've been a lot happier. For one thing, Bob would've been forced to interact with other people face-to-face, and if he started spewing his hateful shit he would've gotten his face punched in until he learned to keep it to himself. This is a lesson modern-day Bob has never learned, much to his detriment.