Teenager's Tattoos

Tattooing has become for young people more fashionable. One reason may be that they like to carry a picture on their body, but sometimes such a picture or symbol is attached to belonging to a social group, and sometimes to a radical one.
I think parents should give their children some freedom to get their bodies tattooed, but if they are a kind of radical group and may hurt other people, they should be banned. The Philosopher said taht a person's body is the mirror of the soul, but if the soul is violent or aggressive, then, it´s better not to be represented with tattoos on their body. We are talking about those whose way of thinking is mainly violent.