WEDNESDAY, Aug. 13 (HealthDay News) -- Even infidelity has its price, new research suggests.

Would-be participants in an extramarital affair tend to calculate both the economic and biological benefits beforehand, researchers from the University of New Hampshire (UNH) and Bryant University report.

But factors that go into the decision differ slightly between men and women, said study author Bruce Elmslie, an economics professor at UNH.

Women weigh factors including financial stability, education and whether the man is a good candidate to father a child, Elmslie wrote in a university news release.

"These factors do not come into play for men who, overall, are 7 percent more likely to cheat than women," he added. "The likelihood of a man having had an affair increases with age, and reaches a peak when a man is about 55 years old. It then decreases with age. For women, the peak is 45 years old."

"The benefits of female infidelity reduce after the age of 40 because a woman would no longer benefit in terms of improved gene quality from the affair," he said. "Men also experience a reduction of sperm quality around the age of 45, but the reproductive benefits of an affair extend further into a man's lifetime than a woman's."

The study also found:

• Upper-class women are 8 percent more likely to cheat than other women, while men are equally likely to cheat among all economic classes.
• Men who have gone to college are 3 percent less likely to have an affair than other men, while educational status has no impact among women.
• Unhappy men are 13 percent more likely to have an affair, while unhappy women are 10 percent more likely to do so.
• Religious women are 4 percent less likely to cheat, while religion has no impact on whether men have an affair.

The study is published in the current issue of the journal Kyklos.

More information

Genetics might play a role in infidelity, according to the BBC.