Only unmarried female physicians, who worked longer hours, earned more than their married counterparts with children, but their added earnings did not buy greater happiness.

Dr. Davis said preliminary analysis suggested that such men tended to eat poorly compared with their married counterparts.

Cohabitants, or couples who spend at least four nights a week together, are likely to face many of the same difficulties as their married counterparts, experts say.

Ms. Thompson believes that suburban single women are distrusted by their married counterparts.

As a result, they are far more likely than their married counterparts to raise their children in poverty.

In one of which, Rachel plays Jiexi, a seductress who lures away her married counterpart, Li Tianming.

The unmarried couples tend to be younger and more racially mixed than their married counterparts and are almost as likely to have children living with them.

They, too, show lower immune-system function than their married counterparts, and get sick more often - but not as often as the men.

Other matches, often held in front of large crowds with heavy betting on the side, pitted single women against their married counterparts.