Smell Test

While being able to smell androstenone may seem like an attribute that you can live without, the chemical may have some broader implications than making us scream "ewwww." Or in the case of some women, "aaahhh."

But so far scientists know less about androstenone's effects on humans than its effects on pigs. And what they do know about pigs is enough to make any researcher blush. The chemical, which is found in large concentrations in the saliva of male pigs, acts like an aphrodisiac among the porcine set.

Once female pigs catch a whiff of androstenone they immediately assume a posture called lordosis, replete with a curved back and wiggly haunches. "Essentially, they ready themselves for mating," says Wysocki. Because of that rapid, well, response, human marketers have jumped on the androstenone bandwagon, hawking male deodorants and sprays that promise to make men irresistible to women.

"At this point there isn't any scientific evidence that a spray of androstenone is going to help any guy get lucky," says lead researcher Leslie Vosshall, Ph.D., the Chemers Family Associate Professor and head of the Laboratory of Neurogenetics and Behavior at Rockefeller University. "Plus, if the woman he's hot for doesn't have a functional copy of the gene, she won't even smell it." And of course there's always that pesky problem that she may simply perceive it as stale urine mixed with some Armani.

But men shouldn't give up yet. Researchers have already shown that the complex soup of chemicals that comprise "man sweat" can elicit some unusual physiological responses in some women: an increased heart rate, a better mood and sexual arousal. Male sweat can also effect the secretion of luteinizing hormone, which is involved in stimulating ovulation.

"There is a lot more to male sweat than it just being a funny anecdote," says Vosshall, who plans a series of studies that use the genetic find to determine the compound's role in social hierarchies. Since men with high levels of testosterone sweat out equally high levels of androstenone, "the question is, will a woman respond to those levels, will she, in a sense, sniff out the manliest man in a group?" says Vosshall.