DNA-based matchmaking offered by Toronto's Instant Chemistry

Can DNA testing help you find love?Controversial genetic tests that claim tohelp match singles based on their DNA are being offered by a Toronto company.

Sara Seabrooke, co-founder and chief science officer of Instant Chemistry, says the company's genetic and psychological testing service can help "narrow down the field" of potential dates and help you find a good match.

"Right now, matchmaking is basically based on an art," she told CBC's The Current Tuesday. "And there's the science available that we can use, and why not provide it and let people have the opportunity to use it if they want to?"

• Hear the full interview on The Current

For $199US, Instant Chemistryoffers two genetic tests based on a saliva sample, along with a psychological test. It then compares your results to others in its database to find potential matches it considers genetically compatible.

Seabrooke said one genetic test is linked to how strongly people respond to emotions, and a 13-year study of married couples suggested it could predict marital satisfaction.

"If you have two people who come together who are both responding very strongly to emotional situations in their life, it can lead to volatility," she added.

The other genetic test is based on a study in the 1990s that had women rank the attractiveness of men by smelling T-shirts they had worn for several days. The "sweaty T-shirt" study found that women were more attracted to men who had more different immune system genes matches that might generate children with healthier, more diverse immune systems.

"The research is definitely there," Seabrooke said.

• Friends share similar DNA, study finds

But not everyone is convinced.

One problem is that the "sweaty T-shirt experiment" has been controversial.

Daniel Davis, a professor of immunology at the University of Manchester and author ofThe Compatibility Gene, said some scientists have criticized the methodology. Women were asked to read a particular book before smelling the T-shirts, and there were questions about whether a different book may have generated different results.

There is also some debate about how reproducible the study was.

Seabrooke saidthe results have been replicated by different labs around the world.

But Arthur Schafer, director of the Centre for Professional and Applied Ethics at the University of Manitoba, saidsome researchers have been unable to replicate the results.

"It's not really science," he said. "The evidence is pointing in all different directions."

Evidence hard to interpret

Even if the results are valid, they're hard to interpret, Davis said.

For example, someone might prefer certain body scents, but it's not clear whether that affects their actual behaviour.

Mice certainly prefer to mate with other mice with different immune system genes, but they identify those mice by smelling their urine.

"And that's clearly a skill lost in us," Davis said.

He also suggested that narrowing the field down to those with different immune system genes might not narrow the field much at all.

He and his wife got their immune system genes tested and compared with18 million others. It turned out only four people had the same set of genes as Davis, and only a few hundred had those of his wife.

Davis doesn't think Instant Chemistry's service does any harm, but he suggests that "people should immerse themselves a little bit in the science behind that" before deciding whether to sign up for the service.

Schafer suggests people should just save their money and focus on other characteristics they might look for in a mate, such as their looks and sense of humour.

"Of all the things that are important, I would think that this [immune system compatibility] would rank way down," he said.

He added that people can always screen their dates for an attractive scent the old-fashioned way.

"Instead of spending $199, try kissing and snuggling for a bit."