Doug in the comments linked to a column by Natalie Angier in the New York Times. The column is worth a post all its own, because of this:
Small wonder that many Darwinian-minded observers of human mating customs have long contended that serial monogamy is really just a socially sanctioned version of harem-building. By this conventional evolutionary psychology script, the man who skips from one nubile spouse to another over time is, like the sultan who hoards the local maidenry in a single convenient location, simply seeking to "maximize his reproductive fitness," to sire as many children as possible with as many wives as possible. It is the preferred male strategy, especially for powerful men, right? Sequentially or synchronously, he-men consort polygynously.
Women, by contrast, are not thought to be natural serializers. Sure, a gal might date around when young, but once she starts a family, she is assumed to crave stability. After all, she can bear only so many children in her lifetime, and divorce raises her risk of poverty. Unless forced to because some bounder has abandoned her, why would any sane woman choose another trot down the aisle — for another Rachael Ray spatula set? Spare me extra candlesticks, I'm a one-trick monogamist.
...
Yet in a report published in the summer issue of the journal Human Nature, Monique Borgerhoff Mulder of the University of California, Davis, presents compelling evidence that at least in some non-Western cultures where conditions are harsh and mothers must fight to keep their children alive, serial monogamy is by no means a man's game, finessed by him and foisted on her. To the contrary, Dr. Borgerhoff Mulder said, among the Pimbwe people of Tanzania, whose lives and loves she has been following for about 15 years, serial monogamy looks less like polygyny than like a strategic beast that some evolutionary psychologists dismiss as quasi-fantastical: polyandry, one woman making the most of multiple mates.
Doug also jokingly wonders if this refers to some loose piece of feminist research, and of course it's hard to know without reading the actual research. But if research consisting of following a tribe for fifteen years, recording the number of marriage-like relationships and recording the numbers of children which survive past the crucial age of five is loose research, what the fuck should we call all those ask-the-American-undergraduates-to-rank-pictures-of-desirable-women evo-psycho pieces? So loose that the universe and our brains fall through it?
Let me calm down a bit there. Whatever the quality of this research might be (and I will check if I have time), at least it actually measures reproductive success. The importance of this cannot be overstressed. Practically all the studies I have seen speculate about the reproductive success of men who cast their seed around widely, while not offering actual evidence. Likewise, very few studies address the complaint I've made many times that getting a woman fertilized does not equal having produced a fertile adult offspring. Before that is possible the pregnancy must result in a live birth, the resulting baby must be fed and kept safe all through the next ten plus years. Only then can we measure the reproductive success in the sense of the genes being passed on.
So what were the findings of this study? Here:
In her analysis, Dr. Borgerhoff Mulder found that although Pimbwe men were somewhat more likely than their female counterparts to marry multiple times, women held their own and even outshone men in the upper Zsa Zsa Gabor end of the scale, of five consecutive spouses and counting. And when Dr. Borgerhoff Mulder looked at who extracted the greatest reproductive payoff from serial monogamy, as measured by who had the most children survive past the first five hazardous years of life, she found a small but significant advantage female. Women who worked their way through more than two husbands had, on average, higher reproductive success, a greater number of surviving children, than either the more sedately mating women, or than men regardless of wifetime total.
Angier emphasizes that the results are preliminary. It will be most interesting to follow future studies of this data set.