A British behavioural scientist says women are happier in life when they are unmarried and childless.
And happiness isn't the only benefit for that group of the population - they also live longer than their married and child-rearing peers.
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Professor Paul Dolan from the London School of Economics and Political Science analysed research gathered as part of the American Time Use Survey which compared the pleasure and misery of married, unmarried, divorced, separated and widowed women.
Data from that survey showed that married women reported happiness levels higher than single women, but only when their spouse was in the room.
"Married people are happier than other population subgroups, but only when their spouse is in the room when they're asked how happy they are. When the spouse is not present: f**king miserable," Dolan said while speaking at a book festival in Wales.
Dolan says the survey's evidence showed that traditional markers of happiness such as marriage and children no longer satisfy women.
However, the same can't be said for men, who seem to thrive in a traditional family unit.
"We do have some good longitudinal data following the same people over time, but I am going to do a massive disservice to that science and just say: if you're a man, you should probably get married; if you're a woman, don't bother."
Men benefited from marriage because they "calmed down", Dolan said. "You take less risks, you earn more money at work, and you live a little longer. She, on the other hand, has to put up with that and dies sooner than if she never married. The healthiest and happiest population subgroup are women who never married or had children," he concluded.
Nevertheless, Dolan said single, childless women still face social stigma which could threaten that happiness.
"You see a single woman of 40, who has never had children - 'Bless, that's a shame, isn't it? Maybe one day you'll meet the right guy and that'll change.' No, maybe she'll meet the wrong guy and that'll change. Maybe she'll meet a guy who makes her less happy and healthy, and die sooner."