Infidelity – is it down to genetics?

With the rise in membership at online ‘affair’ websites, why are people in happy, loving relationships still drawn to the lure of an extra-marital affair?


As experienced divorce lawyers, we have dealt with clients from both sides of the infidelity fence, and guided them through the resulting consequences for both partners and their families. We also seek to understand more about what motivates our clients to act as they do, which can lead to cutting-edge theories and research results emerging from the USA.


man and woman in cuddle on seat woman holding hands with another manThe science of infidelity

In a fascinating blog for TED, biological anthropologist Helen Fisher turns a professional eye on the science of affairs. She starts with statistics; while 85% of Americans will marry, up to 40% of married men and 25% of married women will also have an extramarital affair at some time.


The three brain systems

As humans we have three hard-wired brain systems related to love. It’s the complex interactions between these systems that, as Fisher says:

“Makes it biologically possible to express deep feelings of attachment for one partner, while one feels intense romantic love for another individual, while one feels the sex drive for even more extra-dyadic partners.”


This may partially explain why infidelity is embedded in many cultures through the ages. Yet, as Fisher notes:

“Infidelity is a worldwide phenomenon that occurs with remarkable regularity, despite near universal disapproval of this behaviour.”


The genetic theory of infidelity

So, is there any genetic basis for this kind of ‘social disobedience’? An American study** suggests there might be.


The study suggests that men who have a specific gene in a specific location (the 334 vasopressin allele in a specific region of the vasopressin system) experience lower levels of attachment to their partner. Also, men with this 334 gene experience more marital disharmony than those without the gene.

We’re not suggesting that this theory of a genetic predisposition to infidelity is in any way a defence or justification for an extra-marital affair, and certainly wouldn’t advise trying to use it as a reason in court! However, it may go a little towards explaining the persistence of infidelity even when society expressly does not approve of it.

If you have concerns about your spouse’s fidelity, and want to understand your current position regarding any possible divorce, do call us. We offer a free 30 minute consultation to help you assess your financial and legal rights.






** “Genetic variation in the vasopressin receptor 1a gene (AVPR1A) associates with pair-bonding behavior in humans,” by Hasse Walum et al in The Proceedings of the National Academy of Sciences