ABC News (March 27, 1998)
Your Nose Knows Who's Right For You
Sniffing Out a Mate
By Bill Ritter
Fragrance companies have long tried to convince us that a person's smell can drive us into a sexual frenzy.
And scientists are now discovering that when it comes to some sexual choices, we may indeed follow our noses.
That's especially true for women.
"Women are more likely to use their sense of smell to decide whether or not they'll actually go through
with a sexual encounter," says experimental psychologist Rachel Herz,
who studies the complicated relationship between sex and smell at the Monell Chemical Senses Center in Philadelphia.
"It's not so much that women are running across the room saying,
'You smell great, let's get naked,'" she explains, "but rather they're saying,
'You don't smell right, I'm not going ahead with this.'"
And the very survival of our species may hinge on such a judgment.
Sex and Immunity
Just check out this weird science: In Switzerland, women were asked to take a few whiffs of men's smelly T-shirts,
stuffed inside unmarked boxes, and then rate how sexy or unpleasant each T-shirt smelled.
The scientists learned something amazing from this experiment.
The women's reactions suggested they could actually smell differences in the men's immune systems.
Different women liked different T-shirts, and the ones they liked belonged to men
whose immune systems were genetically different than theirs.
So, what does the immune system have to do with sex?
When parents have two very different kinds of immune systems,
their children are born with a sort of combined immune system that can fight off a greater number of diseases.
This scent theory might sound far-fetched, but we do know that this same kind of thing happens in the animal world.
Mice, for example, have the ability to sniff out such genetic differences.
"Immune system genes control odors," says University of Utah biologist Wayne Potts,
"and the different versions of the immune system genes give off different odors."
Signals in Our Sweat
Scientists are learning something else about how we select our mates:
There may be other chemical signals we send each other that we can't smell-signals that carry a wide range
of biological messages. They're called pheromones.
In animals and insects this "chemical command" is irresistible.
For example, when a glass rod is doused with pheromones from a female cockroach,
the males go crazy and actually try to mate with the rod.
But what about humans? Can we be controlled by these subconscious chemical commands?
Biologist Winnifred Cutler thinks so. In fact, Cutler sells products she claims contain pheromones.
And she says her customers report dramatic results.
"I've one guy who said to me, 'Five times a year maybe we had sex.
Since I've been using the pheromone straight, it's five times a week.'"
If You Don't Like Oysters
Cutler is not alone. There are now several products on the market-many of which are sold over the Internet-
that claim they contain sex pheromones. What exactly is in these products?
"I don't know what other people are selling," Cutler says.
"I know our pheromone formula is a closely guarded trade secret."
But other products aren't so secretive.
And some really do contain a chemical that is a sex pheromone-a sex pheromone for pigs, that is.
This magic chemical is called androstenol. It's actually found in male pig slobber.
And one sniff of it makes the sows freeze, ready for sex.
Even a canned version of this pig pheromone has the same effect on the lady swine.
And it turns out androstenol is found in only one other animal. Us.
It's in our underarm sweat, to be precise. Which is why it's now sold as a sex pheromone for humans.
But don't get your hopes up. Scientists we talked to said pig pheromones only work on other pigs.
Human Pheromones Exist. Period.
And what about human pheromones? Psychology professor Martha McClintock of the University of Chicago
has done a new and groundbreaking experiment, just published in the science journal Nature.
"This study, I think, really is the first definitive study that shows that humans have pheromones,"
she says. "We still need to know whether we use them on a regular basis, but they are there."
McClintock took underarm sweat from women at different points in their ovulation cycles,
and then wiped it under the noses of female volunteers.
The result was dramatic: The sweat samples actually changed the length of the volunteers' ovulation cycles.
In other words, the women's bodies were communicating through unconscious chemical commands-
the first scientific proof that human pheromones exist.
Dr. Luis Monti-Bloch of the University of Utah is among a growing number of scientists
who believe humans have a separate organ hidden in our noses to detect pheromones.
Monti-Bloch says you can see it in special microscopic pictures.
It's a tiny pit, called a VNO. Some scientists say we haven't used this organ in thousands of years.
In other words, we have a kind of sex organ.
In our noses. Does that mean pheromone products can really deliver on their promises?
"We're not as simple as a cockroach," McClintock says.
"It's not the case that we're going to have a single molecule that's going to compel us to cross the room."
But skeptics don't deter the pheromone marketers. Winnifred Cutler, for example,
has no doubt her product works.
And she's even published her own study which she says proves her claims.
What seems safe to say, while science sorts all this out, is that when it comes to human sexual attraction,
we're being led around by our noses, more than we think.