In fact, the research to date is all over the place.
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.” Into this complicated field now come direct-to-consumer genetic testing companies such as Instant Chemistry and Singld Out.
In recent weeks, two companies (Instant Chemistry and Singld Out) have made a media splash with their launch of a new direct-to-consumer genetic testing service to help determine compatibility in intimate relationships.
Singld Out is an online dating service that operates via the professional networking site Linked In and uses Instant Chemistry’s genetic testing results to match its members.
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.
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.
Over the centuries, physics, chemistry, and biology have transformed what once was seen as mysterious or even magical—the rotation of the stars, flowers blooming, causes of disease—into well-understood phenomena.
Could the same now be happening to love and lust, the most mysterious and magical of all human emotions?
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.