That's it! Don't buy your kids toys, buy them the real thing! And then teach them the responsible way to use it - yes, morals will be part of the lesson (i.e., NEVER point it at anything you don't intend to kill, treat every gun as though it was loaded and live, etc.). Don't forget the occasional demonstration of what kind of damage it can inflict - a plastic jug of water, a pumpkin, a watermelon, etc.
Age 10 = BB gun
Age 12 = .22
Age 14 = .410
Age 16 = 12 ga. and/or a deer rifle (30.06 or a 30-30, etc.)
Finally, age 18 = a real, honest-to-God self defense weapon like a 9mm, a .357, or a .45, etc.
As the son of an American refinery engineer who spent his single-digit years growing up in a couple of South American countries that could be hazardous to Americans, including pre-Castro Cuba in 1957 and '58, I was used to the idea of maving a loaded submachinegun resting muzzle-down near our front door, backed up by dad's carbine or a shiotgun from a covering doorway. When I reached 7 years and 7 months, I got both a usable .22 and a course of instruction on the buzzgun and carbine, with instructions on wehen to use it or when not to.
One thing that helps: if a kid does get toy guns with which to play in his formative years, it's useful if they're at least authentic in that they actually procect projectiles, whether plastic or foam balls or pellets, darts or a water stream. It helps remind that kid that when the trigger is pulled, something more is going to happen besides a *bang* noise.
I got undermined in my own efforts along those lines with my own kid by his matrernal grandparents, so he had some bad habits that had to be corrected first. Accordingly, he didn't get his first rifle, A Service Model Lee Enfield quite capable of killing a man at a half-mile, until his 12th birthday. There's a bit of a story about that, but there's such a story about any youngster and his first rifle, if you pay close enough attention. In my own case, it was a 12-gauge shotgun I got at about age 14 that turned out to be the real honest-to-God self defense weapon I had when armed visitors with the intent of killing my father were a very likely consideration. A couple of previous incidents were settled without shots being fired, with weapons ranging from a Kar98 Mauser rifle to dad's ex-Air Corps carbine. But when it got serious, I had that thumbbuster Winchester riot gun in hand, and it served me well.
-archy-/-
Ding ding ding! We have a winner! Its that lack of instruction to our nations youth, and the "forbidden fruit" syndrome, combining with criminal activity and the media-induced bloodlust, which is creating these juvenile delinquents.
Teach your children, your grandchildren, or your nieces and nephews proper firearms discipline as early and as often as they can stand it.