Swedish scientists have discovered a 'divorce gene' linked to increased risk of relationship breakdown.
Researchers say the gene affects the way the brain responds to vasopressin, a chemical that is central to the bonding process between partners.
Men with a variant of the gene were more likely to report having marital difficulties and were assessed to have weaker bonds with their wife.
The discovery suggests scientists may be able to develop drugs to help restore struggling marriages by targeting the gene.
Data on more than 550 twins and their partners or spouses were used in the study, conducted by Hasse Walum and colleagues at the Karolinska Institue, Stockholm.
An assessment of gene responding to vasopressin was compared to men's scores in the Partner Bonding Scale, which is designed to measure the strength of a person's attachment to his or her spouse.
It was concluded men with the variant gene had low scores and were less likely to be married.
The wives of those men were also found to be less satisfied with their marriages.
"There are many reasons why a person might have relationship problems, but this is the first time that a specific gene variant has been associated with how men bond to their partners," Mr Walum said.
While Mr Walum stressed the gene could not be used to predict a person's behaviour in future relationships, but said earlier research on the gene in prairie voles revealed boosted levels of vasopressin in the brain made the animals more monogamous.
"The fact that the corresponding gene has proved important for similar behaviour in voles makes our findings even more interesting."
