Your Cheatin' Genes

Did John's genes make him cheat on Elizabeth?
Photo by Mike MurphyI've brought up before how genes can affect our behavior. They don't necessarily determine what we do but they can make doing the "right" thing easier or harder. A new study suggests that having a certain version of a certain vasopressin receptor gene makes a man less likely to cheat on his partner.

The gene commonly comes in three different versions -- RS1, RS3, and GT25. Men with GT25 and RS1 reported more infidelity and had unhappier marriages on average than men with RS3. Which version a woman had didn't seem to matter.

Scientists don't know why men with the RS3 version are more faithful but it makes sense that this gene would be involved. It has been implicated in pair bonding in other animals with the best and most comprehensive work having been done on little rodents called voles.

There are many different kinds of voles but we’ll focus on prairie and meadow voles. Prairie voles stick with one female. Meadow voles are a bit more like men in country music songs -- they tend to love them and leave them.

A bunch of wonderful experiments showed that the voles' different behaviors were because they had different versions of a certain vasopressin receptor gene. People don’t have the exact genetic difference that meadow and prairie voles have. But the exact same gene is involved in this new study.

The vole experiments showed that if the vasopressin receptor works less well in prairie voles, the boy voles develop a wandering eye. And male meadow voles with extra potent vasopressin receptors settle down.

So at least in voles this vasopressin receptor gene is important for pair bonding. We'll need more studies in humans to nail down whether it plays as big a role in human male monogamy. But this study does bring up some interesting ideas.

First off, we aren't voles so having this gene is no excuse for cheating on a partner. It just means that it is harder for these men to remain faithful. Sorry John but even if you have this gene version it doesn’t let you off the hook for cheating on Elizabeth.

Second, if the study proves to be correct, then it suggests that there may be a pharmaceutical way to modify men's behavior. A pharmaceutical company would need to come up with a drug that targets this receptor. Now men who take this drug would be more likely to be faithful. I don’t know about you, but this form of pharmaceutical behavioral modification seems a little scary to me.

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