Redbone's got it here....as long as they understand its not a toy and understand/respect the power. All the evening news horror stories of kids shooting each other are from irresponsible parents keeping loaded guns accessible to kids and failing to educate their kids about them. As such, kids do what kids do and pick up/play with anything that isn't nailed down. Inevitably accidents happen and politicians have a field day with it.
I got a Red Ryder BB gun when I was 8 or 9, a high powered pellet gun a couple years later, and a 1930's Springfield .22 bolt-action 5 shot rifle(that fires and works perfectly) when I was 13 or 14.
I'm hardly a gun enthusiast, but know how to handle one if needed.
There was a section on "conventional wisdom" in the book Freakonomics (a very interesting read btw). There was a case with a mother who refused to let her young kid play at a friend's house because she knew the friend's father owned and kept guns in the house. Instead, she let him go to another friend's house who had a pool. The kid drowned from wandering into the ungated pool. The "unsafe" gun-containing house had everything stored in a locked gun safe, completely out of reach to kids. Statistically, far more kids die each year from drowning in pools than in gun accidents, yet guns have that "fear" factor that pools don't. While accidents are tragic, people naturally want to point the finger at something other than their own irresponsibility.