This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Genetic matchmaking is entering the mainstream. The prospect of meeting and selecting potential romantic partners based upon purported DNA compatibility—until very recently the subject of science fiction from films like The Perfect 46 to independently published romances by Clarissa Lake—has increasingly garnered both scientific and commercial attention. Earlier this year, Nozze, a well-established Japanese dating service, established a DNA Matching Course and hosted a related DNA Matching Party, both first-time offerings in that nation. For 86,400 yen ($790), men are paired with prospective dates based upon 16,000 variations in HLA gene complexes.
Nozze joins a market commercializing the science of attraction that already includes Swiss pioneer GenePartner, Houston-based Pheramor and services that combine genetic and non-genetic profiles like Instant Chemistry and SingldOut. Considerable media attention has been devoted to investigating the science behind these services; unfortunately, both the ethical and sociological implications have received relatively short shrift.
The underlying science itself is hardly convincing. Since the 1970s, researchers have found that variations in the genes of the major histocompatability complex (MHC) play a role in mate selection in mice. Similar patterns have subsequently been found in fish, pheasants and bats, but not in sheep. The possibility that MHC plays a role in human mate selection first arose as a result of a well-known experiment by Swiss biologist Claus Wedekind that is colloquially known as the sweaty T-shirt study. Researchers had men wear T-shirts for extended periods of time before placing the shirts in boxes; then they had women sniff the shirts to rate the former wearer’s sexual attractiveness. They found an inverse correlation between MHC similarity and attraction score.
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Since that time, studies in human beings have yielded mixed results. The most persuasive data come from an investigation of Hutterite couples in North America who appear to display nonrandom MHC assorted mating preferences. But this correlation—giving genetic matchmaking the benefit of the doubt—establishes at most a natural preference, and a natural preference is a far cry from connubial compatibility. To our knowledge, nobody has actually surveyed married Hutterite couples to determine whether MHC compatibility plays a role in their levels of marital bliss, or the quality of their dinner conversation, or the frequency of their escapades between the sheets. On a more global scale, no data have yet established a relationship between MHC compatibility and lower divorce rates.
One must ask precisely what we mean by compatibility. At the most fundamental level, couples with MHC-dissimilarity (and thus more so-called mating compatibility) demonstrate lower rates of spontaneous abortion. The dissimilarity may also increase genetic polymorphism, which in turn may lower the manifestation of recessive diseases. However, the impact of MHC-dissimilarity on either of these phenomena is likely to prove relatively small, and therefore should not be expected to play a significant role in the marital happiness or cohesion of many couples.
In addition, genetic polymorphism may help species survive environmental challenges—yet evolutionary advantage is probably not a major variable that most couples consider when seeking romantic bliss. One cannot also ignore the unknowns: Matching couples based on MHC markers may pose some survival benefits, but nobody knows at what cost; it is theoretically possible that the offspring of such couples are also more aggressive or less creative, just to name two traits arbitrarily—and magnifying these effects artificially might prove significantly deleterious to our civilization in the long run.
Harvard geneticist George Church has championed another version of compatibility. Using whole genome sequencing, he hopes to match couples so as to reduce or eliminate many recessively inherited diseases. In Ashkenazi populations, the Committee for Prevention of Jewish Genetic Diseases (better known as Dor Yeshorim) already uses a voluntary testing and matching system to prevent disorders such as Tay-Sachs, Canavan and Niemann-Pick. Church hopes to implement a variation of this program for couples everywhere, claiming it could end some 7,000 genetic diseases and save 50 million lives a year.
The ethical implications of Church’s proposal are complex. If couples are encouraged to use his pairing system, then those who find love outside the realm of genetic matchmaking and produce offspring with genetic disorders may be unfairly stigmatized. At a more practical level, even if the elimination of recessive illnesses is a social good, it is clearly not the sort of compatibility most daters seek in a matchmaking service.
When most people speak of romantic compatibility, the odds are that they mean factors like temperament, tastes and interests. To date, no study has connected these with any genetic variable. MHC-dissimilarity is as likely to lead to partners with temperamental and aesthetic difference as to those with similarities. Ironically, even compatibility appears to have minimal impact on satisfaction in relationships. Multiple studies have shown that universal traits such as kindness, rather than similarities, are the keys to marital happiness.
Genetic matchmaking reflects two concerning trends in modern society. The first is the pandemic loneliness and search for connection that has arisen in the wake of the breakdown of traditional community structures. To use a metaphor first introduced by political scientist Robert Putnam, we are a society bowling alone. We are increasingly willing to shell out a few hundred dollars or a few thousand yen for anything that smacks of a cure.
Genetic matchmaking also manifests the misguided belief that science can solve all of our problems. Unfortunately, we cannot discover, pay or invent our way out of our isolation. Science may ultimately provide tools that help us rebuild societal cohesion, but without meaningful changes in social policy and human behavior, science alone has little to offer. In this case, the science in question is, at best, being misused—and arguably not science at all.