A new study by psychologists at the University of Toronto and Tufts University shows that a woman can more accurately identify a man’s sexual orientation when looking at his face, when she is closest to her time of peak ovulation. Further, having romantic thoughts or a mating goal heightens a woman’s ability to discriminate between straight and gay men.

“This effect is not apparent when a woman is judging another female’s orientation,” says Professor Nicholas Rule of the Department of Psychology at the University of Toronto, lead author of a new study published in Psychological Science. “This suggests that fertility influences a heterosexual woman’s attention to potential mates rather than merely increasing sensitivity to sexual orientation or nonverbal cues more generally.” – Science Daily