Well first off, it's just common sense. It's how our species evolved.
There's also some pretty scary psychological studies, where male primates raised without a father are unable to control their anger, and manifest a lot of behaviors which are equivalent to what we see in the demographic groups which have high rates of absentee fathers. And of course, if you raise a primate with no parents (total neglect) they become completely insane. Furthermore some of the evidence indicates that these aren't just learned behaviors or lack of learning, but there is detectable physical alteration in the development of the parts of the brain which control social behavior.
But there is empirical evidence too. There are all kinds of statistics correlating lack of one or more parents (especially the father) with drug abuse, teen pregnancy, violent crime, you name it? It's one of the leading indicators of major dysfunction.
Do you know any teachers? Ask them about young boys who don't have a father or a stepfather or a father figure.
I'm not saying all people with one parent are automatically going to be losers. But it's raises the odds against them being a functional member of society.
It pisses me off that people think toejam like what Rosie is doing is OK. That's great, just keep spawning them, and we'll keep locking them up.
