A new study reveals that men with masculine features are more attractive to fertile women.
But women with masculine-looking partners do not necessarily become more attracted to their partners, said the study from University of Colorado at Boulder.
A "masculine face" has a relatively pronounced chin, strong jaw, narrow eyes and well-defined brow, like George Clooney, for instance.
A less-masculine face, on the other hand, would include a less-pronounced jaw and wider eyes, a la Pee-wee Herman.
"When they rate men's sexiness, in a sense, that's when (women) show the shift. If they rate men's attractiveness as a long-term partner, then they don't show it," Steven Gangestad told LiveScience.
Masculine facial features suggest that a man is of good genetic quality, because he had the resources during development not only to survive but also to expend energy on a macho visage. Rugged-looking jaws and eyebrows are signals of testosterone.
However, Christine Garver-Apgar says the lack of a similar effect with intelligence is perplexing.
"That we didn't find any effect of men's intelligence on their partners' sexual interests across the cycle is important because some evidence suggests that intelligence associates with genetic quality."
She added that further research is required in order to answer this along with other questions.
The findings come from a study published recently in the journal Evolution and Human Behavior.