It's all how you're raised in my opinion. Take me for example, I grew up watching horror flicks with my father religiously. I'd seen every horror film made by the time I was seven years old, yet the thought never entered my mind to kill somebody brutally.
Parents these days, my generation's a dying breed. Most of the people I've met my age are as well off as I am, but anymore, parents will pay such close attention to their children but once they hit that teenage age, they shoo them right out the door. Then when their kids go off on a killing spree, they say, "I just don't know what went wrong." That's right, they
didn't know.
http://www.wlky.com/news/15357661/detail.html
About as close as you'll get to an update.