Women's "gaydar" better at this time of month: When?

(CBS) Talk about women's intuition.

Research has shown that women are pretty good at guessing men's sexual orientation from a quick glance, and a new study shows that gals' "gaydar" gets even better when they're ovulating.

For the study, psychologists at the University of Toronto and Tufts University had 40 female college students look at 80 photos, each showing the face of either a straight or gay man. The men were considered equally attractive and showed the same facial expressions. When the students - all heterosexual and none of whom was taking contraceptive medication - were asked to say which guys were straight and which gay, they did better if their menstrual cycle schedule suggested they were nearing peak ovulation.

Next, the researchers asked 34 women to look at a similar series of female faces, 100 of which featured gay women and 100 of which featured straight women. What happened? The study participants proved to be no better at guessing women's sexual orientation when they were nearing peak ovulation than when they weren't.

What's the take-away message?

Lead author Nicholas Rule, professor of psychology at the University of Toronto, said in written statement that the findings suggest that "fertility influences a heterosexual woman's attention to potential mates rather than merely increasing sensitivity to sexual orientation or nonverbal cues more generally."

Or - to put it in simpler terms - when women have the greatest chance of getting pregnant, they're better at finding a fellow who's eager to do the deed.

The study was published in the June 27, 2011 issue of Psychological Science.