Men Can Smell Fertility, Study Says

ByMelanie Axelrod

April 5, 2001 -- Chanel says every woman has her own "Allure." But a new study suggests the female allure isn't bottled, rather, it comes naturally.

Researchers at the University of Texas at Austin, used already worn T-shirts to determine that men may be able to smell when women are at their most fertile, regardless of the perfumes and cosmetics they may wear.

Devendra Singh, a psychology professor at the University of Texas in Austin, asked women to wear one T-shirt at night during the most fertile phase of their menstrual cycle (13-15 days after their previous period), then wear another T-shirt during the infertile phase of their cycle (days 21 to 22).

Aside from acquiring two previously unworn cotton T-shirts, the women were also given unscented clothing detergent, soap, and shampoo to use for the duration of the study. They were asked not to wear perfume, and avoid products and foods that would emit a strong odor. They were also asked to refrain from sexual activity and to not share a bed with anyone, not even a pet, during the study.

After use, Singh presented the T-shirts to a group of men and asked them to rate the smell of the worn garments. Out of the 21 pairs of T-shirts, the men could detect a more "pleasant" or "sexy" T-shirt in 15 pairs of them. That breaks down to 15 of the 42 shirts were considered pleasing, vs. the rest that were considered not pleasing, or not detectable.

The results remained detectable even after putting the T-shirts away for a week before they were re-tested.

"Advertising tells us to use perfumes, and wash yourself like crazy to attract males," Singh said. "But it may not be the case."

Smelling Good, Looking Good

Singh concedes, there are a lot of factors that contribute to the attractiveness of a woman to a man. Visual factors perhaps play the greatest part, considering humans are what Singh considers to be "visual animals." But scent, he suggests, may be equally alluring.

The main scent the men in the study may have zeroed in on were likely pheromones says Singh, but might also have included other factors. Pheromones are hormones released from both men and women that are believed to be odorless and consciously undetectable to the human nose. They are believed to promote sexual feelings and urges.

Most smells are detected by a part of the nose that sends signals to the Cerebral Cortex, which is the part of the brain associated with higher order thinking and conscious behaviors. But pheromones are believed to be detected by a group of cells in the nose called the Vomeronasal organ, which then, in turn sends signals to areas of the brain associated with more primitive behaviors and emotions and controls hormone release through the endocrine system.

Singh believes there is a link between the most fertile time of a woman's cycle, and her confidence and social level.

"I think when women are ovulating, the underlying motivation for them is to smell good, so that men will like them," he said. "When women are ovulating, they dress better, and the feel better and more attractive. They are more intrigued by erotica, and more sociable."

The findings, Singh believes, may lead the way to understanding how human ancestors may have selected mates and may even help treat infertility. In essence, his study says humans may be clouding some women's ability to get pregnant by either taking oral contraceptives, or by masking the natural scents that women emit at different point of her cycle.

Researchers: Smells Like the Truth

Lynne D. Houck, an associate professor at Oregon State University in Corvallis, Ore. believes the study does bear some truth, but says the T-shirts don't tell the whole story.

"The waters are a bit muddied in the terms of human behavior," said Houck. "There's so much else that goes into human mating that's also physical and psychological when dealing with humans."