This issue has been fairly controversial in behavioral research (along with violent television viewing). The research has gone back and forth, but the best studies, last I heard, did indicate an effect of violent media exposure (so not specifically video games) on aggressive behavior later in life. This was in longitudinal research after controlling for other variables such as parent history of aggression, child's prior history of disruptive behavior, SES, etc. So, using anecdotal data like the representative reportedly did is, of course, not a sound way to make policy decisions (wouldn't it be nice if politicians were required to learn the basics of science and technology [and ethics] before being eligible to "serve"?), but there is some scientific basis for the concern.