Also, he says, kids can become desensitized to violence. "When you're exposed to violence day in and day out, it loses its emotional impact on you," Huesmann said. "Once you're emotionally numb to violence, it's much easier to engage in violence." Read how children may not outgrow bipolar disorder
But Dr. Cheryl K. Olson, co-director of the Center for Mental Health and the Media at Massachusetts General Hospital in Boston, isn't convinced.
"It's not the violence per se that's the problem, it's the context and goals of the violence," said Olson, citing past research on TV violence and behavior.
There are definitely games kids shouldn't be playing, she said, for example those where hunting down and killing people is the goal. But she argues that the label "violent video games" is too vague. Researchers need to do a better job at defining what is considered a violent video game and what constitutes aggressive behavior, she added.
"I think there may well be problems with some kinds of violent games for some kinds of kids," Olson said. "We may find things we should be worried about, but right now we don't know enough."
Further, she adds, playing games rated "M" for mature has become "normative behavior" for adolescents, especially boys. "It's just a routine part of what they do," she says. Read why food allergies in children are on the rise
Her advice to parents? Move the computer and gaming stuff out of kids' rooms and into public spaces in the home, like the living room, so they can keep an eye on what their child is up to.
Dr. David Walsh, president of the National Institute on Media and the Family, a Minneapolis-based non-profit, argues that the pervasiveness of violence in media has led to a "culture of disrespect" in which children get the message that it's acceptable to treat one another rudely and even aggressively.
"It doesn't necessarily mean that because a kid plays a violent video game they're immediately going to go out and beat...