It's the question famously posed in the classic rom-com 'When Harry Met Sally': Can men and women just be friends if they find each other attractive? A new study claims to have the answer: no.

Researchers from the University of Wisconsin-Eau Claire asked men and women to list the pros and cons of having opposite-sex friends. Thirty-two percent said feelings of attraction were a bad thing, while only six percent listed such feelings as a benefit.

Women were more likely to describe attraction as a drawback, according to the study. Forty-seven percent of women age 18 to 23 said attraction was a negative in opposite-sex friendships, while 22 percent of men said the same.

Moreover, the study showed that opposite-sex friendships can actually harm romantic relationships. Thirty-eight percent of women and 25 percent of men age 27 to 50 said jealousy from their romantic partners resulted when attempting to maintain opposite-sex friendships at the same time. And the more attraction they felt in opposite-sex friendships, the less satisfied they were by current romantic relationships.

So why is this the case? Researchers think that interacting with the opposite sex triggers mating strategies that evolved tens of thousands of years ago. "Mating strategies," they said, "may influence people’s involvement in cross-sex friendships to begin with, as well as unintentionally color people’s feelings toward members of the opposite sex with whom their conscious intent is platonic."