I disagree globetrotter (altho you certainly have a right to your opinion).
I think that ANYTHING a child is allowed to do irresponsibly or without restraint (read: parental guidance) is a weakness that can turn into a detractor as the child gets older and matures into an adult.
Weapons or anything else can be used in an irresponsible way.
I do agree however that it is the responsiblity of the parents to provide guidance (whatever the issue is at hand).
Nothing is impossible for the person that doesn't have to do it.