Is beauty more than meets the eye?

Women find a masculine face--with a large jaw and a prominent brow--more attractive when they are most likely to conceive, according to a study published in the June 24 NATURE. Before, during, and just after menstruation, however, they seem to be drawn to less angular, more "feminine" male faces, the researchers report.

"Other studies of female preference, mainly for odors, show changes across the menstrual cycle," says lead author Ian Penton-Voak of the University of St. Andrews in Scotland. "We thought it would be interesting to look at visual preferences and see if they changed also."

The researchers showed 39 Japanese women composite male faces that emphasized masculine or feminine facial features to differing degrees. The women preferred images with more masculine features when they were in the fertile phase of their menses but favored more feminine features during their less fertile phase.

The type of face women find attractive also seems to depend on the kind of relationship they wish to pursue, according to another experiment. The cyclic preference for masculine faces was evident among 23 British women asked to choose the most attractive face for a short-term relationship, Penton-Voak says. The 26 women asked to choose an attractive face for a long-term relationship, however, preferred the more feminine features throughout their menstrual cycle.

Another 22 women who were using oral contraceptives did not show monthly changes in the faces they preferred even for short-term relationships, indicating that hormones might play a role in determining attractiveness, Penton-Voak says.

Men whose faces have some feminine softness are perceived as "kinder" men who may make better husbands and partners, he adds, while macho features may be associated with higher testosterone levels and good genes. He cautions, however, that research hasn't yet shown a link between a woman's preferences in such tests and her actual behavior.