Infidelity: Brought to you by the Internet (thanks a lot, Al Gore!)

New studies reveal that "younger women appear to be cheating on their spouses nearly as often as men."

How many are we talking about? "University of Washington researchers have found that the lifetime rate of infidelity for men over 60 increased to 28 percent in 2006, up from 20 percent in 1991. For women over 60, the increase is more striking: to 15 percent, up from 5 percent in 1991."

In other words, almost three out of ten men have cheated on their wives by the time they hit 60; meanwhile, 1.5 women out of ten have cheated on their husbands. Another survey shows that in any given year, 12 percent of men and 7 percent of women say they have had sex with someone who isn't their spouse. Which sounds about right. For the youngest cohort of happily marrieds, women and men have achieved rough equality when it comes to deceiving their spouses.

Why the increases for both men and women?

Personally, I have no idea, but researchers advance a number of theories. On the female side, it is likely that more women are just more likely to report infidelity--but it's also the case that contemporary women, who spend less time with young children, just have more opportunities to cheat.

In the past, said Helen E. Fisher, research professor of anthropology at Rutgers, men have wanted to think women don’t cheat, and women have wanted men to think they don’t cheat, "and therefore the sexes have been playing a little psychological game with each other."

On a practical level, being universally charged with care of young children also pretty much zeroed out opportunities for extracurricular sex for the moms. (As most caregivers of preschoolers know all too well, the Little Children scenario, in which a stay-at-home dad and stay-at-home mom get it on while their respective kids nap every day at the exact same time, is very unlikely.)

And as women gain more personal freedom and sexual mores loosen, more women are fessing up to infidelity. It's probably not a coincidence that in urban areas the youngest group of husbands and wives also earn more or less the same amounts of money.

These days, "married women are more likely to spend late hours at the office and travel on business. And even for women who stay home, cellphones, e-mail and instant messaging appear to be allowing them to form more intimate relationships." One Atlanta psychiatrist who specializes in family crisis and couples therapy told the New York Times "he has noticed more women talking about affairs centered on 'electronic' contact."

Technology might also be driving male infidelity. Researchers blame the widespread availability of pornography on the Internet, which is known to affect sexual behavior, as well as the invention of Viagra, which essentially makes sex outside of marriage possible for senior citizens.

OK then. People are cheating more, or at least becoming more likely to cop to it. And this activity is being facilitated by technology.

But what's interesting about these studies is that it appears to still be the case that most people, a two thirds majority, don't ever cheat. That goes for men (who are still vastly more likely to admit that they do it) as well as women. You'd expect that over the course of a lifetime most baby boomers (because that's the group we're talking about here) would have dallied at some point--but empirically it appears that they have not.

I've often thought that the stereotypical notion that men think with their sexual organs (and its corollary, that women never do) is fundamentally flawed; this usually goes hand in hand with the idea that men are by nature emotionally stunted.

Of course, men have rich emotional lives and their relationships with women are more than just sexual. Quite a few studies of womanizing husbands suggest that it is emotional, not just sexual, craving that motivated them to cheat. (I'm not suggesting anything about the maturity of these emotional needs; that's a separate issue.)

I think few people would dispute that men are, in general, more consistently horny than women. That makes a certain amount of biological sense: men are constantly producing sperm but women's hormonal cycles make proneness to arousal more periodic.

However, as I think most wives (secretly?) realize, the vast majority of men deal with this mismatch through covert masturbation, not cheating. Frankly, it's a complementary part of married life for men, and not a few women.

Neither sex is a slave to its biology; our bodies may provide the raw material, as it were, but morality, emotion, and imagination (which allows us to imagine long-term consequences) play much stronger roles in regulating our day-to-day behavior than biological drives ever will.