I Love Your Genes! - Online dating sites use DNA to make perfect matches.

image
In recent weeks, two companies (Instant Chemistry and SingldOut) have made amedia splash with their launch of a new direct-to-consumer genetic testing service to help determine compatibility in intimate relationships. SingldOut is an online dating service that operates via the professional networking site LinkedIn and uses Instant Chemistry’s genetic testing results to match its members. DNA results become part of each user’s profile, and members can search for and evaluate potential matches based on their genetic compatibility.

Author

GARY MARCHANT

Gary Marchant is Lincoln professor of emerging technologies, law, and ethics and faculty director of the Center for Law, Science, and Innovation at ASU.

YVONNE STEVENS

Yvonne Stevens, J.D., LL.M., is a faculty associate at ASU's Sandra Day O'Connor College of Law, where she is also a Center for Law, Science & Innovation research fellow.
  • Instant Chemistry and SingldOut are not the first to promote genetic testing to determine romantic compatibility. In 2008, a company called GenePartner began to offer genetic testing to identify relationship compatibility. Applying a similar concept are “pheromone parties” in which singles sniff well-worn T-shirts worn by members of the opposite sex to facilitate biological matches based on pheromones, the elusive compounds of attraction.
  • Unlike some direct-to-consumer genetic testing companies (such as those claiming to offer genetically tailored nutritional supplements, which have been subject to enforcement by the Federal Trade Commission for deceptive claims), there is some legitimate science behind the new DNA-matching dating websites.
While genetics seems to play some role in human sexual attraction, it clearly is not the only, or even predominant, factor determining human mate choice. SingldOut claims that genetic tests can identify up to 40 percent of the chemistry of attraction between two people. While not denying that genes play some role in mate selection, Mike Dougherty of the American Society of Human Genetics contends that the research to date does not support quantifying the impact of genetic attraction.
  • In fact, the research to date is all over the place. It has long been known that other mammals, such as mice, selectively mate with partners having different genetic variants of their MHC genes, which control immune responses. A leading hypothesis is that such “disassortative” mating will produce offspring with greater diversity in their MHC genes that will protect them against a broader range of pathogens.
  • Given that all mammals display similar genetic mechanisms, one might expect a similar genetic attraction to exist in humans, albeit within the context of the greater complexity of human relationships. Indeed, a 1995 study found that single women, asked to smell and pick from sweaters worn by men, were disproportionately inclined to pick one worn by a man with different MCH alleles from their own. This suggests that our preference for a particular mate is influenced by our sense of smell, as is the case with other mammals. Similarly, a 2006 study found that the more differences in MHC genes between a romantic couple, the more likely the female partner was to be sexually satisfied and committed to her existing relationship.
  • Yet, as noted above and as is common for most genetic research, especially as it relates to complex human behaviors such as love and romance, the data supporting genetic attraction is highly inconsistent. A large number of studies, involving different experimental methods and populations, have now been reported, and they give discordant results. While some research has supported the theory that MHC gene diversity drives human attraction, other studies have reported different or conflicting results.
A few studies have found that humans prefer sexual partners with only moderately different or even similar MHC variants, others have found that MHC diversity is detected by facial shape rather than smell, and still more have found that women in committed relationships are most attracted to men with different MHC alleles. Some studies have also discovered that women on birth control pills tend to prefer men with the same MHC variants, the opposite of their peers not on the pill. As one scientific review of the entire body of data concluded, “the mixed evidence … makes it difficult to draw definitive conclusions, [but] the large number of studies showing some MHC involvement suggests there is a real phenomenon that needs further work to elucidate.”

Read more

image

In recent weeks, two companies (Instant Chemistry and SingldOut) have made amedia splash with their launch of a new direct-to-consumer genetic testing service to help determine compatibility in intimate relationships.