Committed men less attracted to fertile women.

Would you leave your hubby alone in a room with a fertile young woman whose ‘ready-to-mate’ hormones were inviting a roving eye? (Hint: She’s less of a threat than you think.)  

In this study, a group of men—some single and some in committed relationships—interacted with a woman at various points in her menstrual cycle, and then rated her attractiveness. The woman kept her appearance simple (no makeup, ponytail, jeans and a t-shirt), standardized her behavior (neutral responses, no flirtation) and even used unscented beauty products. That way, any changes in her perceived attractiveness would be due to fertility-related cues, like her scent.

Lo and behold, the woman’s fertility provoked opposite reactions depending on a man’s relationship status.

Single men found the woman more attractive when she was highly fertile (the typical response). But committed men bucked the trend: They found her less attractive when she was at her most fertile.

Why? Men in committed relationships may downplay the attractiveness of a potential new mate in order to preserve their relationships—an unconscious effort to stay faithful. What a refreshing idea!

You’ve heard it before: Human attraction is, at its core, all about making babies. When they’re fertile, women become more attractive to men, whose sole priority in life is to “spread their seed.”

But if you’re rolling your eyes, you know there’s more to the story. Our minds have surprising power over our attraction. We may be turned off by a mean personality or a desire to protect a monogamous relationship, or we might be more interested in people who look familiar.

Our culture and relationships influence who we’re into. Attraction is rarely as simple as spreading a seed. (Honestly, we’re glad for it!)