Noo.. Children are not mature enough to determine if they want something on their body that will stay there forever. Not to mention it is a very painful procedure for a child, and could be considered cruel if a parent endorses it.
SURE THEY SHOULD!! Right across the forehead!!! Swastikas are in high demand these days :) I'm 34 and I don't have a tattoo or a piercing or any of that jargon, it should ALWAYS be a concious choice made by an individual with the proper mental capacity, not something forced upon someone.