If you could test a potential mate to determine whether he or she would cheat on you, would you do it? Is such a test even possible? And are some individuals really more likely to cheat?
Monogamy is defined by sexual exclusivity— monogamous individuals have a single sexual partner for a given amount of time. Monogamy has several documented benefits, such as fewer sexually transmitted diseases, greater investment in childcare, and for humans, financial and emotional stability. But whatever the benefits of monogamy may be, it is a fact that many organisms that form pair bonds find ways to have sex outside of the bond—that is, many supposedly monogamous individuals cheat on their mates. Humans are no exception, and given the costs incurred by cheating, it makes sense to evaluate how faithful a potential partner will be.
Therefore, it is no surprise that reports of a “monogamy gene” are popular and intriguing. But does such a thing exist? How could a gene affect fidelity? And can we actually test a mate’s tendency to stray?