If a relationship is filled with rows or a marriage comes to an end, men may wonder what went wrong.
But scientists say the answer could lie in a woman's genes.
For the first time, they have identified a female 'divorce gene' that can predict a rocky marriage and identify women who may struggle to commit to their partner.
Women who inherit the variation of a common gene are less likely to get married in the first place as they find it harder to bond with other people.
But if they do marry, they are 50 per cent more likely to report a troubled relationship filled with marital strife. Perhaps unsurprisingly, partners of women with the gene are also more likely to report being unhappy.
Women produce oxytocin naturally, but particularly during childbirth and while breastfeeding. It helps them bond with their baby.
But if women cannot process oxytocin properly, they may not be able to bond normally with other people – including their partners, friends and children. It may even be linked to autism, the researchers say.
A Swedish team examined the DNA of more than 1,800 women and their partners. Each couple had been together for more than five years, and were either married or living together.
Women who were identified as carrying the variation of the oxytocin receptor gene, described as the A-allele, were 50 per cent more likely to report 'marital crisis or threat of divorce'. Men married to these women were also far less satisfied in their relationships.
The lead researcher, Hasse Walum, from Stockholm's Karolinska Institute, said: 'We've found evidence that oxytocin can be involved in the regulation of human pair-bonding by showing that variation in the oxytocin receptor gene is linked to how strongly women bond to a partner.'
The same team found the male version of the divorce gene in a study four years ago. It affects how the brain used the chemical vasopressin, which in turn affects men's ability to commit and remain faithful.
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Swedish researchers said Tuesday what women have suspected all along: that marital woes can often be attributed to men's genetic make-up, according to a study linking a common male