Adult children of divorced parents are more likely to get divorced themselves, compared to those who grew up in two-parent homes, research has shown. Now, a forthcoming study in Psychological Science suggests that the reason may have more to do with nature than with nurture. In other words, an increased risk for divorce may be coded in our genes.
To determine whether genetic factors play a role in couples’ likelihood of divorce, researchers in the United States and Sweden analyzed population data from nearly 20,000 Swedish adults who’d been adopted as children. They found that the adoptees were more likely to resemble their biological parents and siblings when it came to their histories of divorce, not their adoptive ones.
This was surprising, says first author Jessica Salvatore, PhD, assistant professor of psychology at Virginia Commonwealth University—since it goes against commonly held beliefs that divorce runs in families because children watch and learn from their parents and grow up to mimic their behavior.
“A lot of the scientific evidence to date has suggested that seeing your parents go through a divorce contributes to your own propensity to experience divorce yourself,” says Salvatore. “But those studies haven’t controlled for the fact that those parents are also contributing genes to their children. By looking at adopted children, we’re able to separate out the genetic factors and the environmental ones.”
Salvatore says the newly discovered hereditary connection is likely due to personality factors that have also been linked to genetics—like neuroticism and impulsiveness. “We know from other studies that these are factors that contribute to divorce,” she says. “They may make it more difficult for someone to stay in a relationship, or for someone to want to stay in a relationship with them.”
But Salvatore wants to emphasize that just because divorce appears to have has a genetic component, it doesn’t mean that people whose parents split up are destined to do the same. “This is absolutely not a perfect predictor,” she says. “It’s simply an increased risk, just as if you had a parent with an alcohol-use disorder, you’d also be at increased risk for developing one yourself."
The environment you were raised in still matters, too, she says. In fact, the study also looked at data from more than 80,000 adults who’d been raised by a biological mother and a stepfather. In that sample, the researchers did find correlations between participants’ divorce rates and the divorce rates of their biological fathers, with whom they did not live. But their mothers’ marital history (with their stepfathers) was an even stronger predictor of their own marital success—providing some evidence that childhood environments affected future divorce risk “above and beyond” genetic influences alone, the authors wrote.
Salvatore hopes her research can help people better understand the many factors that may put couples at risk for divorce. “We all bring liabilities into our relationships, whether we come from a happy, harmonious home or a troubled and fractured home,” she says. “And knowing how those liabilities work may help people reflect on and improve their own behavior in relationships.”
It may also help guide therapists and counselors in making recommendations for couples who are struggling, she adds. “Other research has suggested that children of divorced parents lack commitment to their relationship,” she says. “But our findings really suggest that it may have more to do with certain personality factors, and that we may have to take a different approach in working with them.”
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Neurotic people, for example, tend to interpret their partners’ behavior more negatively than objective observers do, says Salvatore. “If a clinician knows this is happening, he or she can help reframe—through cognitive behavioral therapy—that person’s perception of events in their relationship,” she says. “It can take the edge off of their interactions, so they're less hostile and give their partner the benefit of the doubt.”
Because the study looked at Swedish individuals, Salvatore can’t say for sure that the findings would translate to an American population. There are a lot of similarities between the two cultures, she says, but also some significant differences. The average age at marriage is higher in Sweden, for example, and the divorce rate is higher.