I'll be the first woman to post on this thread.
The thing is, there is no "better gender" for a single parent. Children learn from both the father and the mother and when one is absent, it changes things.
There are great male single parents, there are great female single parents. There are single parent females who shouldn't have the children and there are single parent males who shouldn't have the children. I don't think it's a matter of which gender is better, but rather which person is stable enough (emotionally, financially, etc.) to take care of the children.
While courts/judges/the law are, admittedly, easier on women and tend to give women the custody of the children, it could be because generally the male is the one with the problems. It is generally the father who is abusing/being violent, or using alcohol, etc. Is that the case for every single one? No. Far from it. There are women who do the same thing. But in
general, it is usually the male and that's why you see the children going to the mother more often than not. As for divorces where violence is not involved and it's just a matter of "differences" between the parents, it's just the way society is in that the justice system is more lenient towards women. That's not really fair and I don't have an answer for why it is on that one.
Like I said, though. I don't think one is "better than the other". Males should be the leader in the family, yes, but that does not make them the "better parent". Both mother and father have a role.