From The Mercury News:

Do you want to reduce shootings? Educate. No young person I have ever known who has been taught proper gun safety and taught the seriousness of handling/owning a firearm has ever committed any criminal shooting. I teach Boy Scouts gun safety and marksmanship. Anyone is welcome to come when we have a class and I promise you will be impressed by how seriously Scouts as young as 11 take this.

Make firearms taboo and that is exactly what a young person will want to get their hands on.