"One of the key genetic rules in breeding dogs, horses or any other kind of thoroughbred is that close inbreeding tends to magnify the weak points in a bloodline as well as the strong points. In horse breeding, for instance, there is a definite risk in breeding two fast horses who are both a little crazy. The offspring will likely be very fast and also very crazy. So the trick in breeding thoroughbreds is to retain the good traits and filter out the bad. But the breeding of humans is not so wisely supervised, particularly in a narrow Southern society where the closest kind of inbreeding is not only stylish and acceptable, but far more convenient — to the parents — than setting their offspring free to find their own mates, for their own reasons and their own ways. (“Goddam, did you hear about Smitty’s daughter? She went crazy in Boston last week and married a nigger!”)"