Field Guide to the Cougar

Latin Name: Femina Magnus

Notable Characteristics: 40-plus woman on the arm of a significantly younger man. Financially independent and well educated. Looks younger than her age.

Songs & Calls: "I'm not his mom." "Can you keep up with me?"

Origin of the Species

The evolution of the cougar label is murky, but the term's surge in popularity seems to stem from a 2001 book called Cougar: A Guide for Older Women Dating Younger Men, penned by Toronto Sun columnist Valerie Gibson. "I had a friend who told me about this awful bar," Gibson recalls. "There was a woman there who was flirting with younger guys. He said, 'She looks like a cougar on the prowl.' I decided to make it a term for women 40-plus who date younger men and don't want to settle down." Other experts have expanded the definition to include older women who have long-term relationships with and marry men 10-plus years their junior.

Cougar in the Media Glare

The cougar craze has reached a fever pitch, with Hollywood rolling out productions that manage to both glamorize and mock the archetype. Witness Courteney Cox as the hot-but-hapless cradle-robber in Cougar Town, Sex and the City's middle-aged and sex-crazed Samantha Jones, and a Bachelorette-style reality show dubbed The Cougar.

Society, however, hasn't exactly embraced real-life "cougars" with the same fervor as Tinseltown's producers. Earlier this year, Carnival Cruise Lines dropped its second annual "Cougar Cruise" for older single women and younger single men—even though the first voyage drew 300 spirited attendees. And Google stirred up controversy a few months ago by banning the dating site CougarLife from its content pages. (In contrast, "sugar daddy" dating sites and portals that pair up unhappily married people for affairs are as Google-able as ever.) Clearly the older woman/younger man pairing, though more on-the-radar than ever, is not sitting well in our psyches.

That aversion, in turn, is rankling so-called cougars. In a small study about marriages in which the women were 10 years older than their husbands, wives said they bore the brunt of the backlash. Men may receive some gentle ribbing for marrying an older bride but manage to brush it off better, says University of Maine researcher Nichole Proulx, Ph.D. "Women are socialized to be extremely conscious of how they look, dress, and act, so if they do something outside of the norm, they fixate on it more so than men," she says.

Cougars in the Wild

Though women who date younger men might feel like societal outcasts, their ranks are growing: The number of marriages where the woman is 5 to 10 years older than her spouse is small (5.4 percent and 1.3 percent, respectively), but rates have doubled between 1960 and 2007, according to census data.

It's not hard to explain the trend—females live longer, they're financially independent, and they look hotter than ever (think: Restylane and retinols). "You couldn't tell by looking at our subjects that the wives were a decade older than their husbands," admits Sandra L. Caron, who coauthored the University of Maine study. Plus, women say a younger man carries less emotional baggage, tries harder at romance, and exhibits refreshingly equitable views on gender roles. ("He does his own dishes!") Men say they love that older women don't play mind games, and their established careers are inspiring—not emasculating.

What's more, it might make evolutionary sense for an older woman to seek a younger mate. As women decline in fertility, their sex drive gets a supercharge in order to maximize their remaining baby-making chances, new research from the University of Texas at Austin reveals. Women in the low-fertility group (ages 27-45) were much more likely to report having more sex, wanting more sex, and having more (and more intense) sexual fantasies. "If you're trying to maximize your remaining fertility, it makes sense to seek out a younger partner because his sperm is healthier," says lead researcher Judith Easton.

Cougar Phobia

You might think the cougar backlash stems from the fear of older women poaching guys from young women. ("Find someone your own age!") But our resentment likely has deeper roots.

One theory: The pairing dredges up associations with the incest taboo—a taboo that's ingrained across almost all cultures, says Christopher Ryan, author of Sex at Dawn: The Prehistoric Origins of Modern Sexuality. Humans developed aversions to sex between family members, so seeing a young man with his arm around a more senior woman might touch on the same incest associations and leave people feeling squeamish. An older man with a trophy wife can spark similar disgust.

A more common (and intuitive) theory maintains that these couples aren't at the same desirability level, a mismatch we find aversive. Men can reproduce late in life, so an older man with a nubile woman makes more evolutionary sense than an older woman with a man in his prime. Psychologist Nigel Barber, author of The Science of Romance: Secrets of the Sexual Brain, says our gut reaction to the incongruency reflects how we quickly size up a person's mate value: by his or her looks.

Humans are hardwired to notice attractiveness, a marker of youth, health, and fertility. Evolutionary psychologists acknowledge that good looks are more important for women's dating desirability than men's and that female physical attractiveness declines more rapidly with age. So a young man on the arm of an older woman looks like he's dating below his level. The exception? If the woman's smoking hot (think: Demi Moore), she's not judged as harshly because the pair's mate values appear equal, Barber says.

Ryan draws parallels between the backlash against a less fertile older woman with a virile young man and the recent uproar about gay marriage. Eliciting similar tacit disapproval are other forms of non-procreative sex: sexually active senior citizens, gay sex, and children displaying any traces of sexuality.

Despite the deep-seated resistance to this type of relationship, some experts think the tide is turning. Ryan predicts the phenomenon will follow a path to acceptance similar to homosexuality's. Today, the majority of college-aged people approve of gay marriage, in stark contrast to attitudes just a generation ago.

Acceptance might not be too far off. Cheryl Covey, 67, and Stuart Mark Berlin, 53, have lived together for the past five years. "Our families were horrified at first," Berlin says. The only ones who didn't make a fuss? Her teenage grandkids.