What are the effects violent video games have on children

Depends on the games, if they're playing a game thats rated E that doesn't connect to the internet, they'll learn hand eye co-ordnation and how to usee video games as a stress releaver. If they play a game thats rated T, M, or Ao with online acess, they will learn how to swear and insult other peoples mothers, and will likely make bad dessicions based on the things they see in the game.

As long as they stick to games apropriate for their age, the effects will be mostly possitive save for maybe them wanting to stay up late so they can defeat the monster and save the world.