New research says boys are just as catty as girls.

Here's a shocker: Teen boys are just as likely as girls to spread nasty rumors, gossip and intentionally exclude others, according to a new study conducted by the University of Arizona.

Wait a minute--- aren't girls supposed to be the bitchier sex?

"These conclusions challenge the popular misconception that women are the aggressive sex," says lead author Noel A. Card, an assistant professor of family studies and human development at the University of Arizona.

Card and his team analyzed the behavior of 74,000 children and teens. And despite the belief that girls are the cattier ones (thanks very much "Mean Girls" and "The Hills"), it was boys who struck the lowest blows.

The research included both physical aggression (pushing, tripping,) and social aggression (gossiping, name calling), which is intended to ruin a teen's social standing in his peer group.

And get this: Boys who are physically aggressive are more likely to exhibit ADHD-type symptoms, poor relationships with peers, and a refusal to help out or share with others. While social aggression is related to depression and low self-esteem.