In most cases, it is considered a natural, normal behavior in children of all ages.
Children often begin masturbating at around eighteen months of age.
Masturbation tends to peak when children are between the ages of three and five. It then declines in frequency until puberty. Parents should keep in mind that masturbation generally causes no physical harm to their children. In most cases, problems result only when adults overreact. For parents to deal with their children's masturbation they must know when it is normal and when it might indicate some underlying problem.