Note: this is just a theory, developed in reaction to recent conversations.
Let us assume, first of all, that men and women have different optimal reproductive strategies, based on their different anatomy. In case you have not experienced birth yourself, it’s a difference of calories, time, and potential death.
In the ancestral environment (before child support laws, abortion, birth control, or infant formula):
For men, the absolute minimal paternal investment in a child–immediate abandonment–involves a few minutes of effort and spoonful of semen. There are few dangers involved, except for the possibility of other males competing for the same female. A hypothetical man could, with very little strain or extra physical effort, father thousands of children–gay men regularly go through the physical motions of doing just that, and hardly seem exhausted by the effort.
For women, the absolute minimal parental investment is nine months of gestation followed by childbirth. This is calorically expensive, interferes with the mother’s ability to take care of her other children, and could kill her. A woman who tried to maximize her pregnancies from menarchy to menopause might produce 25 children.
If a man abandons his children, there is a decent chance they will still survive, because they can be nursed by their mother; if a woman abandons her child, it is likely to die, because its father cannot lactate and so cannot feed it.
In sum, for men, random procreative acts (ie, sex) are extremely low-cost and still have the potential to produce offspring. For women, random procreative acts are extremely costly. So men have an incentive to spread their sperm around and women have an incentive to be picky about when and with whom they reproduce.
This is well known to, well, everyone.
Now, obviously most men do not abandon their children (nor do most women.) It isn’t in their interest to do so. A man’s children are more likely to survive and do well in life if he invests in them. (In a few societies where paternity is really uncertain, men invest resources in their sisters’ children, who are at least related to them, rather than opting out altogether.) As far as I know, some amount of male input into their children or their sisters’ children is a human universal–the only variation is in how much.
Men want to invest in their children because this helps their children succeed, but a few un-tended bastards here and there are not a major problem. Some of them might even survive.
By contrast, women really don’t want to get saddled with bastards.
We may define sociopathy, informally, as attempting to achieve evolutionary ends by means that harm others in society, eg, stealing. In this case, rape and child abandonment are sociopathic ways of increasing men’s reproductive success at the expense of other people. (Note that sociopathy doesn’t have a formal definition and I am using it here as a tool, not a real diagnosis. If someone has a better term, I’m happy to use it.)
This is, again, quite obvious–everyone knows that men are much more likely than women to be imprisoned for violent acts, rape included. Men are also more likely than women to try to skip out on their child support payments.
Note that this “sociopathy” is not necessarily a mental illness, (a true illness ought to make a dent on one’s evolutionary success.) Genghis Khan raped a lot of women, and it turned out great for his genes. It is simply a reproductive strategy that harms other people.
So what does female sociopathy look like?
It can’t look like male sociopathy, because child abandonment decreases a woman’s fertility. For a woman, violence and abandonment would be signs of true mental defects. Rather, we want to look at ways women improve their chances of reproductive success at the expense of others.
In other words, female sociopathy involves manipulating or coercing others into providing resources for her children.
But it’s getting late; let’s continue with part 2 on Monday. (Wednesday is book club.)