Oct. 14, 2010 -- A man with a masculine face is much more likely than a guy with less masculine features to keep his partner's sexual attraction during her fertile period, known to be the time when a woman's eye can wander, according to a new study.

For guys not born with George Clooney's face, there's more bad news. Even being super smart won't help him compensate, it seems. "Even if women are with an intelligent man, they are just as likely to look around during their fertile phase," says Steven Gangestad, PhD, a professor of psychology at the University of New Mexico, Albuquerque.

His study, adding to growing information about how a woman's preferences for mates change across the menstrual cycle, is published in Evolution and Human Behavior.

Women's changing preference for mates as their menstrual cycle evolves has been researched for about a dozen years, Gangestad says. "When women are fertile, they prefer masculine traits, such as deep voices and muscular bodies," Gangestad tells WebMD, citing the body of research to date.
Masculine Faces vs. Intelligence

For the new study, Gangestad wanted to know if certain characteristics of men would influence a woman's tendency during her fertile period to be sexually attracted to someone other than her partner.

In this study, he looked specifically at the masculinity of the face and the man's intelligence independently.

Researchers consider a masculine face one that has a more pronounced chin and jaw, with eyes not typically as wide open as a woman's, Gangestad says.

As examples, Gangestad says, he would consider the face of TV character Pee-Wee Herman to be on the feminine side, and the face of George Clooney very masculine.

For the new study, Gangestad interviewed 66 romantically involved heterosexual couples, with the women ages 18 to 44. They were in relationships ranging in duration from one month to 20 years, and nine of the 66 couples were married.

After gathering background information on the participants, including an IQ test given to the men, the researchers asked the women to answer questions when they were in their highly fertile period, as verified by a fertility test, and during a non-fertile time of month.

The women reported whether they felt strong sexual attraction to their current partner and whether they felt sexually attracted to someone else --acquaintance or a stranger -- over the previous two days.

Women also reported whether they fantasized about having sex with someone other than their partner in the two days before answering the questionnaire.
Sexual Attraction During a Woman’s Fertile Period

''If women are paired with men who are more facially feminine," Gangestad says, "what we found is they are the ones particularly likely to be attracted to men other than their partners during their fertile phase. Overall, women are reporting the greater attraction to someone other than their partner in the fertile mid-cycle, rather than the non-fertile phase."

Sexual Attraction During a Woman’s Fertile Period continued...

He says it probably has to do with women equating masculine faces to a ''robustness" thought to reflect overall good health. "The idea is that women are particularly attracted to individuals who have this robustness characteristic that may benefit their offspring," he tells WebMD.

Gangestad wanted to test the idea that intelligence might trump looks or at least compensate for a less-than-masculine face.

Intelligence didn't factor in, he found. "Even if they are with an intelligent man, women are just as likely to look around during their fertile phase."

Whether a man is intelligent or not doesn't seem to play a role. It's the masculinity of the face that counts, Gangestad says.
Sexual Attraction May Not Equal Action

His latest study didn't explore whether the women with the roving eyes went beyond their fantasies and feeling of sexual attraction, Gangestad says.

While the results support the idea that the attraction to someone other than the partner occurs, "that is not to say they act on their preferences," he says.

Other research suggests that men may have a sixth sense about that roving eye, Gangestad says. "Men are a little bit more attentive to their partners mid cycle," he says, citing previous studies. Men somehow seem to detect a woman's fertile phase, he says.
Women Seeking 'Good' Genes?

The new research builds on what experts in the field, including Gangestad, have found, according to Rob Burriss, PhD, a researcher at the University of Chester in Enlgand who studies mate retention and choices.

"The research shores up the original theory that increased preferences for masculine men when women are fertile serve to increase the likelihood of women seeking so-called 'good genes' in other men," he says. "If women's partners already have these good genes -- that is, if they are masculine -- there is less need for women to seek those qualities elsewhere."