In an op-ed in the NYT Sunday Review (May 24, 2015), “Infidelity Lurks in Your Genes,” Richard Friedman states that:
We have long known that men have a genetic, evolutionary impulse to cheat, because that increases the odds of having more of their offspring in the world.
But now there is intriguing new research showing that some women, too, are biologically inclined to wander, although not for clear evolutionary benefits.
I’ve never been sold on this evolutionary explanation for male cheating, but I wonder why it’s assumed women wouldn’t be entitled to it as well. For the male’s odds of having more offspring to increase, the woman has to have the baby, so why wouldn’t the woman also get the increased odds of more offspring? It’s the woman’s offspring too. Moreover, the desire to have babies tends to be greater among women than men.
I guess it’s because a woman’s procreation rate more or less maxes out at one baby per year, and for most of our evolutionary past, women would typically be not far short of that from age 12 until they died (quite probably in childbirth). Few men, on the other hand, will have been hitting their theoretical annual maximum, which for men of the ages we evolved to live to is 365 times some constant in the range 1-.