“I knew I would marry my husband the minute I smelled him,” admits psychologist Estelle Campenni in the cover story of the February issue of Psychology Today.

The article is all about the role smell plays in sexual chemistry. And here you thought you were finally being honest by shallowly admitting that attraction was ultimately about looks.

According to the PT article, while sexual attraction remains one of life’s biggest mysteries, “some researchers think scent could be the hidden cosmological constant in the sexual universe, the missing factor that explains who we end up with.” The reason we feel “chemistry” with one person and not another.

And the explanation for why so many of us end up with people who possess none of the traits we claim to be looking for.

James Kohl and Robert T. Francouer have been on to this theory for years. Their 2002 book The Scent of Eros: Mysteries of Odor in Human Sexuality brought together years of research on smell and sex, and they also claim that you may like everything about someone, but if you don’t like the way they smell, forget it. Especially if he or she smells like someone you’ve turned up your nose at in the past.

“In reality,” Kohl believes, “we make the odour association first and the visual association thereafter.” Hey, blame it on TV — we’ve become a visual society, plus the fact that walking up to someone and taking a big whiff might be considered a tad impolite.

However, Kohl says there’s no need to bury your nose in someone’s underarm to figure out if you like them. The connection is subliminal. That’s because of things called pheromones, chemical molecules that are created when stimulated by something from our social environment — like a totally hot guy, for instance. These are not consciously detected “smells,” that is, until they hang out in your sweat and party with some bacteria for awhile. That’s when things get nasty and you cross the line from turn-on to turn-off. According to these guys, these subtle body aromas are hot-wired to our brain. “Pheromones travel directly to the lymphoid system, the emotional centre of our brain,” says Kohl. That’s where the frisky hormones hang out that subsequently make us stare and drool.

Francoeur, Kohl and PT aren’t the only ones who’ve made the smelly sex connection. Researchers at the Smell and Taste Treatment and Research Foundation in Chicago tested floral and perfume smells on men aged 18 to 64 to see how odours would affect them sexually. One researcher threw in a fake cinnamon bun smell for fun and surprisingly, it got the most enthusiastic response. They decided to test a whole slew of food odours and, though some had a more stimulating effect than others, they discovered that all food smells tested increased penile blood flow.

Before you go spreading cinnamon buns all over your body, the researchers admit that seeing as pumpkin pie was the biggest turn-on, it could just be a case of feel-good nostalgia.

Even Kohl and Francoeur agree that a big part of smell response goes back to memory and learned associations. Kohl calls this “olfactory imprinting” and likens it to visual imprinting for a duck. “If the first thing a baby duck sees is its mother, it will follow her around. If it sees a basketball, it’ll follow that. Same with olfactory imprinting.” Following this logic, if you like the smell some guy leaves on your pillow, you’ll probably start following him around, too.

While no one’s come out with an eau de pumpkin perfume, the fact that we plaster ourselves with artificial odours just reinforces how important odours are in human behaviour, says Kohl. “Our natural body odours are considered offensive, so we go ahead and apply animal pheromones, things like musk and other perfumes derived from animals.”

Doesn’t this throw us off the scent? “Not really,” says Kohl. “You can never really get rid of natural body odour, but you can mask it, make it a little different. You’re basically reestablishing a chemical identity for yourself once you’ve removed your natural chemical identifiers.”

So does this mean that all our hard work on finding and maintaining relationships is futile, because it all comes down to “I don’t like the way you smell, honey?” Kohl admits that, unlike animals, which rely almost solely on smell to choose their sexual partners, we humans are differentiated by our intellectual capacity. And how much our intellect overrides our natural odour associations remains to be determined, says Kohl.

As someone who’s always had a lousy sense of smell, this suddenly makes some of my past relationship choices make a lot more sense.