New research suggests that being happily married may have less to do with chance and more to do with genes.
Researchers at the Yale School of Public Health, New Haven, CT, investigated how a gene variant that influences the so-called love hormone oxytocin might contribute to marital satisfaction and security.
The researchers invited 178 married couples aged between 37–90 years to complete surveys about their feelings of satisfaction and security in their marriage. Each volunteer also gave saliva samples for genetic testing.
The results showed that when at least one of the partners in a couple carried a particular version of the oxytocin-related gene, both partners reported greater marital security and satisfaction.
"This study," says first author Joan K. Monin, who is an associate professor of public health, "shows that how we feel in our close relationships is influenced by more than just our shared experiences with our partners over time."
"In marriage, people are also influenced by their own and their partner's genetic predispositions," she adds.
Oxytocin and its receptor variants
Throughout the evolution of "many species, ranging from invertebrates to mammals," oxytocin, which is a hormone and chemical messenger, has been present.
In recent years, numerous studies have demonstrated oxytocin's impact on different emotional and social behaviors and functions, ranging from social memory to bonding, social stress, empathy, and trust.
Oxytocin exerts its effect by binding to its corresponding receptor protein. The recent study focuses on variations that occur at location rs53576 on the oxytocin receptor gene OXTR.
The variation, or single nucleotide polymorphism (SNP), can result in an A or a G version. An SNP is like changing a single letter when spelling a word.
As each person inherits two copies of a gene, this means that this particular SNP has three "genotypes:" GG, AA, and AG.
Individuals who carry GG versions or who have GG genotypes of the SNP "show greater empathy, sociability, and emotional stability," write the authors. They also note that studies of close relationships have linked these attributes to "better relationship outcomes."
However, they believe that their study is the first to investigate links between partners' oxytocin receptor gene variants and their marital satisfaction and security.
GG genotype tied to 'greater marital satisfaction'
For their investigation, the researchers analyzed feelings of marital satisfaction and security against the GG, AG, and AA genotypes of the individual spouses.
The analysis showed that individuals with a GG genotype or whose partner had a GG genotype "reported greater marital satisfaction than individuals with AA or AG genotypes."
Partners that both had a GG genotype accounted for around 4 percent of the variance in marital satisfaction.
The team suggests that while this figure seems low, it is not insignificant given the many other factors — environmental and genetic — that can influence couples.
The results also revealed that individuals with a GG genotype reported less "anxious attachment" in their relationship, which also helped their marital satisfaction.
Monin explains that studies have linked anxious attachment to having a high sensitivity to rejection, feelings of low self-worth, and "approval-seeking behavior."
The authors conclude:
"Results of this study suggest that having at least one spouse in a marriage with an OXTR GG genotype is associated with both partners feeling satisfied and this is because spouses feel more securely attached to one another."