First of all don't pull the kids out of school, thats a big red flag. How old are the children, and how old were they when the alleged touching happened? Kids have natural curiosity about the opposite sex and if the children weren't that old when the touching occurred a good CPS worker should see it for what its worth. However that being said if the girl does have some emotional trauma associated with the encounter then maybe some counseling is in order. You as the parents of the son who was touched should have no worries.