It's a scientific fact that men have shorter life expectancies than women. But a new study investigating wildlife may have an unusual explanation: sex.

Scientists at England's University of Cambridge studied 20 different vertebrate species and discovered that a competition for sex resulted in a quicker death for males, LiveScience.com reports.

In a polygynous species (the red-winged blackbird, savannah baboon, most humans), males are forced to compete more for female affections, and are more likely to age faster and die earlier.

"The researchers explained that as competition among males for sex grows more intense, each male on average has less time to breed," the article explains. "As such, there is no strong incentive to evolve longevity among males in such species."

The theory follows that monogamous males have a better chance at enjoying a longer life - a revelation that could rock many a playboy's world.

Be sure to forward this to your boyfriend or husband!