Marital fidelity doesn’t come easily.

When the cheating website Ashley Madison was hacked in 2015, it was revealed that the company had some 37 million users. The same year, in a YouGov survey, one in five Americans admitted to being unfaithful.  

If these numbers don’t persuade you, consider the words J.R.R. Tolkien wrote to his son in a 1941 letter.

“No man, however truly he loved his betrothed and bride as a young man, has lived faithful to her as a wife in mind and body without deliberate conscious exercise of the will,” Tolkien wrote.

Tolkien’s words suggest that the struggle to remain faithful is not unique to our age, but one that stems from human nature. Still, new research suggests there are ways to spot that potential cheater—even if the findings are a bit unsettling.

University of Nevada Reno’s Daniel Weigel and Texas Tech University’s Dana Weiser (2017) conducted a series of studies to determine if infidelity is learned behavior—learned, that is, from one’s parents.

Psychology Today has an overview of the three studies Weigel and Weiser conducted:

“The research team first established that, as predicted, people whose parents were unfaithful were more likely to accept the favorability of infidelity, and then be more likely to engage in cheating behaviors themselves. Such factors as trust and feeling confident in their own ability to be happy in a relationship played no role. However, the second study revealed that parental infidelity was not directly related to offsprings’ beliefs about infidelity. The authors reasoned that parental infidelity alone, therefore, isn’t enough to set the stage for beliefs by their children about whether or not they felt cheating was acceptable. Instead, in the third study, which included a larger and more diverse sample than the previous two, Weiser and Weigel examined the potential intervening role of parental communication regarding infidelity. It’s one thing to grow up in a home where a parent is having an extramarital affair, but doing so discreetly, and another where it’s evident, either from the parent’s behavior or from overhearing the parents arguing, that infidelity is taking place.

This older and more diverse sample also reported a higher level of infidelity than was true for the other two, with one out of three participants stating that they had been unfaithful at some point in one of their relationships. Additionally, a main focus of this third study was whether parental communication about infidelity would have an impact on infidelity beliefs which, in turn, would predict reports of cheating. Participants rated how much statements about infidelity were similar to messages they received at home, as well as whether their parents directly told them that infidelity was either desirable or not in a romantic relationship. These family communication measures played a far greater role than mere exposure to parental infidelity.”

The findings strongly suggest that infidelity, to some extent, is cross-generational. A child raised in a home where infidelity is present is more likely to grow into an unfaithful adult. A child raised in a home where infidelity was practiced and communicated openly will be more likely yet.

Weiser and Weigel’s research carries the usual caveats (replication, duration, etc.). But are the results really surprising?

RELATED: “The Scary Reason Most Men Cheat“

Parents have a powerful influence on their children, both through nature and nurture. That many children would learn and adopt—passively or actively—the views and behaviors of their parents, even behaviors and attitudes unconventional or repellant, should not shock us.

But it does raise interesting questions about the idea of sin, if one believes in such a thing.  

The idea that infidelity or any sin affects only the sinner is an attractive one. I, for one, was never comfortable with those parts of the Old Testament that talked about “visiting the iniquity of the fathers on the children, to the third and the fourth generation.” But what if, like a stone thrown into a pool, our choices ripple throughout space and time in ways we don’t quite understand?

In any event, it’s probably prudent to know a potential partner’s views on fidelity before becoming involved with that person in a serious relationship. And it wouldn’t hurt to ask at some point—quite casually—how those views were formed.