Do Women Prefer Different Men When They're Ovulating?

Possibly a little, but researchers disagree. Older studies and a UCLA analysis of 50 studies found that fertile women leaned toward more masculine, dominant men, mostly for short-term partners. A larger, preregistered study of 157 women found no shift in preferences at all. Either way, you can't use it to time anything.

A University of Stirling psychologist, Anthony Little, had women who weren't on the pill pick between "feminized" and "masculinized" versions of the same male body, first for a short-term relationship and then for a long-term one. Fertile women picked the masculine body 15 percent more often, on average, than women who weren't fertile. The effect was strongest when women were choosing a short-term partner and when they rated themselves as attractive.

Little said the takeaway was that women's preferences vary with context, their reproductive cycle and their immediate goals, and that "preferences are not absolute."

UCLA researchers later pooled data from 50 studies, published and unpublished. They reported that preferences shifted during the fertile phase toward short-term, "sexy" traits, and that this preference is limited to the few fertile days. The traits named were masculine body type and facial features, dominant behavior and certain body odors.

Two details matter. The shift was statistically significant but "small" to "medium" in size. And the authors said the evidence was less clear about which male traits matter most.

A preregistered study from the University of Göttingen, published in Psychological Science, tested 157 heterosexual women aged 18 to 35 with regular cycles. Each woman watched videos of a man getting to know a woman who was out of frame, then rated the man's attractiveness for short-term and long-term relationships. They did four testing sessions each. The researchers measured hormones in saliva and used ovulation tests to confirm fertile days.

They found no evidence that women's mate preferences shift across the ovulatory cycle. What they did find:

• Women rated all the men as slightly more attractive when fertile, whatever the men's behavior.
• In every phase of the cycle, men who were more competitive and flirty were rated more attractive for short-term sex and less attractive for long-term relationships.

The lead author said the fertile-phase result "indicates that women's mating motivation is likely to be higher in the fertile phase." The team called it the largest sample to date and said it fits other recent studies that used stricter methods.

Nobody can settle it from here. The honest summary is that the idea of a big, reliable preference flip is not well supported, while a small effect hasn't been ruled out. One result is worth keeping either way. The Göttingen study found that in every phase, flirtier and more competitive men were rated more attractive for short-term sex and less attractive for long-term relationships. That's about the man's behavior, not her calendar.

Don't try to time her cycle. You can't know where she is in it, and as the Göttingen study found, her preferences may not move much anyway. Stress, sleep and mood can all affect how she responds. If you notice she's more flirty and open one week, match that energy. If she isn't, don't chase harder. Stay steady.

Be the provider and the lover. Being dependable earns trust, but it doesn't by itself create excitement. Keep being reliable with plans and logistics, and also show some desire and decisiveness:

• Instead of listing five dinner options, say, "I know a great place. You'd like it. Let's go."
• When she tells you about a stressful day, don't jump straight into fix-it mode. Try: "That sounds annoying. Come here." Then change the mood.
• Instead of paragraphs of texting, send one clean message: "You're trouble. Saturday works for me."

Use the signals that work all month. Make clear eye contact. Speak in shorter, slower sentences. Tease lightly without being rude. Touch with purpose, not hesitation. Step forward or back based on how she responds.

Keep novelty alive in a long relationship. In my experience, attraction fades when a man becomes only the reliable one who handles things. New places, new activities and new energy keep you from sliding into that.

Don't tell a woman she's "fertile" or "ovulating" as a reason she likes you, or as a reason she doesn't. It's creepy, and the science doesn't support that kind of precision. Your job isn't to predict her biology. It's to be a man who's easy to trust and worth being excited about, every week of the month.