Can martial arts training lead to trouble?

Most martial arts teach the theory that the first line of defense is nonviolence. "The spirit of genuine martial arts is the opposite of aggression," says Terrence Webster-Doyle, author and founder of Martial Arts for Peace, an antiviolence group based in Vermont. "It seems contradictory, but by learning to defend yourself, you also learn how to resolve conflict without violence." And it's not like kids become lethal weapons overnight. "By the time a child is competent enough to do actual damage," says Robert Wolfe, Jr., of the Itten Dojo in Pennsylvania, "there's a high likelihood he'll have already learned not to turn to violence."