...	Jennifer Lopez pays attention to what her nose tells her.

By Raj Kaushik

"I'm a very smell-orientated person. I can be attracted to a man almost by the way he smells."

Singer/actress Jennifer Lopez passionately describes her favourite of the five senses in an recent magazine interview.

IN SEVERAL sex surveys, up to 90 per cent female respondents point out that bad teeth and male body odours put them off. Is something wrong with Jennifer? No, certainly not.

Known for their modesty and elegance, some Victorian women used to sell handkerchief soaked in their underarm sweat. For a young woman with the right smell, the shillings were easy to come by.

In general, body odours are perceived to be disgusting and offensive. But contrary to the popular belief, recent research studies suggest that body odours - pheromones, speaking scientifically - can inflict a therapeutic, romantic, turn-on effect upon us.

The word pheromone is composed of the Greek words pherein, meaning "to transfer," and hormon, meaning "to excite."

"Why do bulls and horses turn up their nostrils when excited by love?"

Charles Darwin noted this remarkable observation in his diary. In 1811, Ludwig Jacobson wrote about a tiny sensory organ located inside the nose near the nostril in animals. This organ was called Jacobson's organ or the vomeronasal organ (VNO).

Until recently pheromones were best recognized in animals for their ability to communicate and to attract members of the opposite sex.

The role of VNO in the case of humans has, however, remained ambiguous.

In 1971, Martha McClintock, the University of Chicago psychologist, then an undergraduate at Wellesley College, published a study showing that the menstrual periods of women living together tended to adjust so that they fall on the same time every month.

Now, more than 30 years later, McClintock and her colleagues are reasonably sure that this convergence of menstrual periods is mediated by pheromones. One of the most revealing studies in this context is by McClintock and Kathleen Stern, entitled Regulation of Ovulation by Human Pheromones.

In this study, underarm fluid samples of women were applied to the upper lips of other women in different phases of their menstrual cycles.

The exposed women somehow adjusted their menstrual cycles to match.

These and other studies neither show the exact mechanism as to how body odour molecules interact with our noses nor tell us if the human VNO is active. But they surely suggest that we do communicate chemically, though we may not consciously notice it.

Scientists knew that when female mice sniff around for a mate, they prefer male mice with immune system genes different from their own genes. These genes are called major histocompatibility complex (MHC) genes, and they produce antibodies.

About five years ago, geneticist Carole Ober examined the genetic makeup of 411 married U.S. Hutterite couples. Surprisingly even in this narrow sample, Ober found fewer matching MHC genes than would be expected by chance.

Because the Hutterites, members of a religious order similar to Mennonites, were apparently influenced by their partners' genetic status in choosing spouses, Ober joined with McClintock to test if women could smell the difference in men's MHC genes.

They invited women to sniff T-shirts that a man had worn for two days. The used shirts were placed in boxes where they could be smelled but not seen.

The women were asked which box they would choose "if they had to smell it all the time." The women were not told that they were going to smell a human odour.

The outcome of the study was surprising as well as outstanding. The women could actually smell differences in the men's immune systems. They preferred the odour of man whose genetic makeup was close to their paternal genes, not to their maternal genes.

Julie Mennella of the Monell Chemical Senses Center in Philadelphia asked 45 women who never had given birth, to sniff scented pads four times a day for a month.

Then for the next two months, women were randomly chosen to sniff breastfeeding pads. Twenty-six nursing mothers wore these pads in their bra and under their armpits.

Women smelling the breastfeeding pads reported notably heightened and more enduring sexual desires and fantasies. The study concludes that breastfeeding women and newborns give off odours that arouse other women and encourage them to reproduce.

Devendra Singh, a psychology professor at the University of Texas in Austin, gave a reversal twist to the T-shirt study. He recruited female subjects and asked them not to wear perfume, avoid products and foods that would emit a strong odour, and refrain from sex.

He 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), and then wear another T-shirt during the infertile phase (days 21 to 22).

Singh gave the T-shirts to a group of men and asked them to rate their smell. They detected a more "pleasant" or "sexy" smell in 15 of the 42 shirts.

These studies seem to question ads advocating the use of perfumes all over the spotless body to attract partners, and justify the power of natural pheromones. The area of pheromones is a nosy arena where the opinions of scientists range from gung-ho enthusiasm to outright skepticism.

Perfume makers like Winnifred Cutler and David Berliner are trying hard to prove that their products work as a reliable sex attractant.

But scientists look at their claims suspiciously. They however agree that pheromones do have positive effects on the members of the opposite sex.

We know that physical attraction and love in humans is governed by much more than sweaty armpits.

But now we know that there's something about our sniffers that holds untapped potential for detecting love.

Some scientists even claim that people can lose sexual function if they lose their sense of smell.

Raj Kaushik lives in Toronto.