We’ve all seen him. The big, tough guy brought down by a lowly little bug.

The sniffles he’s enduring are worse than those faced by anyone else in the house — skeptical wives and daughters, especially.

Well, ladies, he might just be the best catch around. That is the conclusion of a new study out of Cambridge University. It found men have weaker immune defences than women, and really do suffer more when hit by a cold or the flu.

“They have traded off immunity for other factors,” lead author Olivier Restif said from his office at Cambridge’s veterinary college. Those trade-offs include getting and keeping mates, which gave them an evolutionary advantage.

Using evolutionary models and mathematical formulas, researchers explored what happens to male and female immune systems over time. Because of the ancestral role of men as the hunter-gatherers, it was assumed males would encounter more infections.

Under most of the models, increased exposure led to increased immunity.

But that’s not what happened with men in the real world. One of the study’s evolutionary models offered a clue as to why. When men have to make an extra effort to attract a mate, they put their energy into that pursuit, leaving their bodies with less ability to fight off infections.

But there could be other explanations. David Begun, a professor of anthropology at the University of Toronto and an expert on human evolution, says women may have built up greater immunities because of their traditional role as caregivers. “The best way to get a cold is to hang around kids,” Begun says.

Being exposed to the viruses and bacteria their children brought into the home, Begun says, women may have become better at fighting them off.