Have you ever found yourself speculating whether cheating is something that just “runs in the family”? Perhaps you’ve heard rumors of infidelity running through generations, or maybe you’ve been concerned about your own relationship habits following the revelation of a parent’s infidelity. The question of why people cheat—and if somehow it is “in our blood”—has captivated scientists, therapists, and ordinary folks for decades. Let’s take a closer look at what the new research reveals about the causes of infidelity, from the science of relationships and personality to the unexpected influence of family history and genetics.
Infidelity isn’t only an overused movie plot device or a secret shared among friends; it’s a real and hurtful experience that touches many relationships. At its essence, infidelity is a violation of trust, usually resulting in emotional anguish, discord, and in some cases, the dissolution of a relationship. But what really foretells an individual’s straying? In response to a close evaluation in the Journal of Medicine, the answer is multifaceted.
Researchers Charlene F. Belu and Lucia F. O’Sullivan discovered that the risk of cheating is defined by a combination of personality, quality of relationship, and situations a person faces. For instance, individuals who score low on conscientiousness—those who are generally disorganized or unreliable—are likely to cheat if their partner is also low in conscientiousness.
High extraversion, low agreeableness, and some “dark” personality traits such as narcissism and Machiavellianism also enhance the chances. Anxious attachment in females and a higher causal-intimacy willingness in males are at greater risk, although the gap between the intimacy is diminishing among younger generations.
But it’s not only a matter of who you are—it’s also a matter of the relationship itself. Couples who score high on commitment and satisfaction are unlikely to be infidel. Those who are having trouble with emotional dissatisfaction are more at risk. Surprisingly, even individuals in what looks like a happy relationship are not immune; opportunity is key. Situations involving a lot of available partners, like some jobs, can make temptation greater, particularly when reciprocated attraction is involved.
So, is cheating truly “in your DNA”? The reply is a definite yes and no. Twin research has presented some of the strongest evidence for an underlying genetic factor. For example, research by Cherkas and colleagues indicated that identical twins, who have all of their genes in common, are likely to both be cheating as opposed to fraternal twins, who have just half.
Heritability of infidelity in these samples is in the range of 40% for women and can be higher in men, as reported by a study done by Zietsch and colleagues. This is to say that genetics explains a substantial portion of the difference in cheating behavior, just as genetics explains traits such as blood pressure or depression.
No single “cheating gene” has been identified, though. Rather, it is probably a mix of risk-taking genes, sensation-seeking genes, and maybe even dopamine regulation genes. As Brendan Zietsch clarified, you may have a genetic predisposition, but that does not necessarily mean you will act on it.
Genes are only half of it, naturally. The world you come from—your family’s relationship dynamics, how conflict is managed, and even how love and trust are expressed—has the power to make a big difference. Children who live with infidelity or come from families with dysfunctional relationship patterns are more likely to replicate those as adults, particularly if they have not had the opportunity to work through or recover from those situations. This is sometimes referred to as “generational sin” or the cycle of dysfunction, where behaviors are unconsciously passed down, not just through DNA but through learned habits and emotional wounds.
But here’s the good news: cycles can be broken. Experts agree that while genetics and family history may set the stage, they don’t dictate your destiny. Owning your decisions, getting help, and navigating hurts from the past will enable you to make a new way. Open communication, healthy boundaries, and management of emotions are paramount, particularly in communicating with children about the past. As marriage therapist Rick Reynolds recommends, learning resilience and making good choices actually becomes a shield against repeating what happened before.
Finally, the biology of cheating shows a messy mix of factors—biological, psychological, and environmental. Though you may be predisposed to a pattern or exposed to certain risks, you can decide how you react. If you’re recovering from betrayal or looking to establish a loyal relationship, learning about these habits is the beginning of breaking them and building healthier relationships in the future.