Is The Concern Over Video Game Violence Valid?

When this debate comes up I notice hard headed advocates on both sides. I usually find that very little critical reason or thought goes along with their opinions. So I decided to examine my own opinion further, and try to come about the complexities of the topic. It certainly is a debate that is ever-changing, just as the graphics in the video game industry increases. The violence for the most part remains steady. Games from years in the past featured brutally killing each other and such, but now it looks more real. Is concern over this correlation valid?