There have seemingly been a spate of cases where a man has been convicted or suspected of murdering a wife or girlfriend pregnant with his genetic child. The most notorious of these recent cases include Scott Peterson, who was convicted of murdering his pregnant wife and their unborn child and was sentenced to death, and Bobby Cutts, Jr., the former police officer convicted of killing his pregnant girlfriend. Marine Corporal Ceaser Lauren has been accused of murdering and burning the body of his colleague, who once accused him of raping her and was likely carrying his genetic child. Why do these and other men kill pregnant women who are carrying their genetic children?
Murdering a woman who is carrying their genetic child is a mystery from an evolutionary psychological perspective, under any circumstances, because these men always have the option of abandoning them. It is possible that some men, under some circumstances, are not capable of investing in their children or willing to do so for various reasons, but in such cases the most obvious course of action is to abandon them. There is absolutely no reason to murder them. Murder of ingroup members has always been heavily condemned throughout human (and probably protohuman) evolutionary history. It is therefore an extreme act. So why, again, do these men resort to it?
From an evolutionary psychological perspective, the answer could not be that these men were afraid that they would be legally established as the genetic father of the child by a court-ordered DNA test and then legally required to pay child support by the court, with the threat of imprisonment if they do not comply. A DNA test, paternity suit, criminal court, and prisons did not exist in the ancestral environment, so men’s brain cannot truly comprehend them and they are not likely to act out of such concerns.
The human brain has difficulty comprehending and dealing with entities and situations that did not exist in the ancestral environment more than 10,000 years ago. This is known as the Savanna Principle. For example, if men’s brain can truly comprehend artificial means of contraception, such as condoms and the pill, then they should not be upset at all if their wives commit adultery when they are on the pill, because the men would then not be cuckolded by their adulterous wives and duped into raising the resultant child as their own. In reality, however, it makes virtually no difference to the men whether their wives were on the pill or using a condom when they engaged in adultery. It would upset them extremely regardless.
By the same token, if men’s brain can truly comprehend the pill, they should not find the prospect of having sex with a young attractive woman on the pill exciting or arousing at all. In reality, of course, it makes virtually no difference whether the woman is on the pill or not; men find the prospect of having sex with her equally exciting. Nor do they prefer having sex with a less attractive woman not on the pill to having sex with a more attractive woman on the pill. This is because the pill did not exist in the ancestral environment, where more attractive women were always more fertile on average than less attractive women.
Similarly, the reason why men are compelled to kill their pregnant girlfriends and lovers could not be that they are afraid that the birth of the child might jeopardize their marriage, because, once again, they always have the option (exercised by countless men throughout history) of abandoning the lover and her child. Throughout evolutionary history, “married” men have often sired children by other women, and their “wives” usually did not care very much as long as the men did not abandon them and their children. It is only when the men are tempted to leave the wife and her children for the other woman that the women get jealous.
In fact, I cannot think of any reason why men should want to kill women. This is an issue (probably the only issue) over which I disagree with my esteemed colleague, and the Dean of Modern Evolutionary Psychology, David M. Buss, the author, most recently, of the book The Murderer Next Door: Why the Mind is Designed to Kill. I agree with Buss that humans probably have evolved psychological mechanisms that are designed, under some circumstances, to compel them to kill all sorts of other people. But not women, their wives and girlfriends in particular. I can clearly see that men are designed, under some circumstances, to rape women, beat up their wives, or abandon them, but I cannot think of any circumstances in which men should be compelled to kill their wives intentionally.
Female reproductive resources are the most valuable resources in the world. I believe that women -- reproductively capable women who would have your children -- are simply too valuable to kill, and it is therefore a great mystery for evolutionary psychology (and, once again, only for evolutionary psychology) why some men do.