Video games for children, teens and young adults bring in $10 billion a year in the United States. Certainly some of the games offer harmless entertainment and maybe even some educational value. But the games that seem to be the most eagerly anticipated, the games that major retailer Zany Brainy says "the industry is focusing on," and the games that fly off the shelves as soon as they're released are those rated "M" for mature and "AO" for adults only.

To garner an "M" rating, the content is intended for people aged 17 and older, and may contain sexual themes and intense violence or language. An "AO"-rated game is suitable only for adults 18 and over, and may include graphic depictions of sex and/or violence.

The popularity of the games is astounding. According to a 2004 report by the National Youth Violence Prevention Resource Center, a 2001 review found that 49 percent of the 70 top-selling video games contained serious violence. Out of all games, 41 percent required violence for the protagonists to achieve their goals. And in 17 percent of the games, violence was the primary focus of the game itself.

The violence is often brutal and degrading to women. In the game "Duke Nukem," for instance, a player can enter a room with naked women saying "Kill me," while tied to posts. In the Grand Theft Auto series, one of the most popular and also most violent and controversial of the games, a player is rewarded if he has sex with a prostitute and then murders her (the most recent of the series, Grand Theft Auto: San Andreas, was the best-selling title in 2004).

Whether or not these games contribute to violent "real-life" behavior among their primary users (pre-teen and teen boys) has spurred major controversy. And, as with most hot-button issues, there are strong proponents and opponents on either side.

Yes, Video Games Cause Violence

Much attention was brought to video game violence after it was realized that the two teenagers behind the Columbine High School shootings played (and even created their own levels of) DOOM, one of the first "first-person shooter" video games (attesting to its popularity, a movie version of DOOM was just released on October 21).

The most recent study on the topic, to be published in the January 2006 edition of Media Psychology, found that playing violent video games does indeed cause violent thought patterns in the brain.

A team of international researchers observed 13 males, aged 18 to 26, for the study. It was found that, after playing a mature-rated game, 11 out of the 13 participants showed significant effects from the games.

"There is a causal link between playing the first-person shooting game in our experiment and brain-activity pattern that are considered as characteristic for aggressive cognitions and affects," said Ren