It's a sitcom trope: The rascally kid does something gross, like bring home a flea-bitten puppy or track mud into the house. Dad doesn't see the harm, but flustered mom launches the full decontamination protocol. Cue the laugh track.

Turns out there's science beyond the stereotype: In several species of primates, including humans, researchers have found that adult females are more sensitive to grossness than males.

For instance, female gray mouse lemurs and Japanese macaques are more likely than males to turn up their noses at contaminated food, while female western lowland gorillas and olive baboons tend to avoid fellow animals with skin infections.

The reason for such fastidiousness? It can lower the females' incidence of disease, from parasitic infections to STDs, scientists say. (Read why humans are hardwired to feel disgust.)

Cécile Sarabian, a cognitive ecologist at the Institute for Advanced Study in Toulouse, France, goes a step further: She suggests that the cumulative effects of female disgust -- being choosier about what to eat and minimizing exposure to infection -- may be one of the reasons why female primates live longer than males.