Is 'Man Flu' Real?

It seems one group may be making the majority of Tamiflu buys. For years, guys have been accused of exaggerating when we don't feel good, but now it turns out the "man flu" may be real after all.

When The Four Seasons said "Big Girls Don't Cry," they probably weren't talking about the flu. Researchers at John Hopkins University say they've figured why women are less likely to get the flu, or at least not suffer from the symptoms as bad.

It turns out it's all because of the female hormone estrogen. Researchers collected cell samples from men and women. Some of those cells were exposed to estrogen or an estrogen-like compound, and then infected with the flu virus.

Scientists found the cells treated with estrogen were more resistant to infections than those left untreated.

Researchers say they wanted to test estrogen against the flu virus since it has also shown promise at preventing other viruses like HIV, Ebola, and even hepatitis.