Two buckets, one blue and one pale orange, are piled with used T-shirts in Ziploc bags for me to sniff. The orange bucket is full of women’s shirts. I open the first Ziploc, and, holding my nose an inch away from a blue striped tank top, inhale deeply. It smells mostly of laundry soap. The second, a white crew-neck, is better, faintly musky and appealing. I scribble down the number “27.”
“Pheromone parties” — singles mixers at which participants anonymously sniff each other’s sweaty T-shirts to find matches with the right chemistry — have been around since about 2010. The idea is to narrow down dates based on biological compatibility, ensuring you’ll find a match who clicks chemically as well as psychologically or physically. Tim Sexton, the shy but affable Australian biologist who waves me towards the piles of soiled T-shirts, wants to take the concept of pheromone parties to the next level. With the power of modern gene sequencing, he says, he can use love-seekers’ DNA to predict who will connect biologically and who won’t.
This is the idea behind DNA Romance, a startup Sexton is launching this week in Vancouver with his wife, Sauder School of Business associate fellow Judith Bosire, and University of British Columbia engineering researcher Abhijit Pandhari. They imagine the service a little like a genetic OKCupid; instead of answering hundreds of questions, users simply supply DNA data, and are matched accordingly. For now, applicants will have to get their genes sequenced by other companies like 23andMe, but eventually the DNA Romance founders hope to take cheek swabs themselves.
The pheromone party they are hosting on the UBC campus is too small for their ambitions. Sniffing through a few dozen T-shirts, I only find two women’s and two men’s I like. With an online database, Sexton and his team want to connect me with thousands.
Sexton came across the surprising science of smell attraction from an unusual source: trees. A researcher on the genetics of the blackbutt eucalyptus tree, Sexton knew that trees practice a genetic tactic called “balancing selection” in which a population carries diverse genes in its members’ immune systems. If a new bug or disease attacks, at least some trees will have the immune genes to survive, and the forest won’t be entirely wiped out.
Humans, it turns out, work the same way. A set of genes called the major histocompatibility complex (MHC) code our immune systems. Diverse MHC genes mean better protection against disease, and a healthier population. That means it’s advantageous to find a mate with different MHC genes to your own so that any offspring will have as robust a collection as possible.
According to a sheaf of recent research, we find such mates through our sense of smell. In blind sniff-tests, we generally find the body odour of people with different MHC genes more pleasant, more bearable, and sexier. Another study showed that in North America and Europe, couples are much more MHC compatible than could be explained by random chance, suggesting we really do pick partners by the genetic smell test.
MHC compatibility, Sexton believes, is the missing factor for instant chemistry on a date. “What I found is that there are genes for that connection, but nobody measures them,” he says. “And I thought, I can measure these. I have the skills to measure these.”
DNA Romance, he says, will specifically analyze about 300 of these genes, then match couples with the greatest number dissimilar. These couples, he believes, will feel the instant click of biological destiny.
When he moved to Canada from Australia, Sexton says he found Vancouver a lonely city, where making a connection was hard. “I’ve used all the sites,” he says, “and if you try out online dating, you go on a date, and she might be nice, or she might be beautiful, but there’s just no connection.”
Sexton doesn’t think genetic testing can replace good old fashioned socializing, but it might facilitate the process. “This isn’t supposed to replace having coffee with someone,” he says. “It’s just to reduce the number of people you have to have coffee with.”
For a second opinion, I spoke to Mark Sergeant, an expert on sexuality and smell at Nottingham Trent University. “In terms of the basic science, the idea is basically sound,” he says. “There’s a trend that people tend to like the smell of MHC dissimilar people. Whether that translates into actual attraction is a completely different matter.”
From years of experience conducting smell experiments, Sergeant says the science of smell is incredibly delicate, and anything from exercise to diet, perfume, bacteria, hormones, and medication (especially birth control) can throw off the scent. “In my honest opinion, I think MHC has an effect, but whether it has a big effect or whether it affects actual attraction is not actually conclusive,” he says. “Matching people for dating based on MHC compatibility is going to be a nightmare to do. There’s so much other stuff, it’s just going to be one variable among many.”
Even so, the science of smell has a lot to tell us about how sexuality works. In his own work, Sergeant has demonstrated that human scent doesn’t just shift based on immune genes, but also on sexual orientation.
In two of his studies, heterosexual women sniffing used T-shirts enjoyed the smell of gay men more than straight men. Another bewildering study by one of Sergeant’s colleagues showed that while, intuitively, gay men preferred the smell of other gay men over straight men, straight men actually preferred the smell of lesbians over straight women, and gay men preferred the smell of straight women over that of straight men. Scientists, Sergeant says, are just as in the dark about why this is, but it suggests our sexual preferences are actually guided by other people’s orientations. Gaydar exists, if only in the nose.
Sexton explains that even without the urge to mate with the opposite sex, queer people still share the biological mechanisms that drive us towards people with contrasting MHCs. Communities with diverse immune systems thrive, gay, straight, or platonic.