The signs can vary from child to child, and some children will not exhibit any signs. However, common things that are observed in children who have been molested include: age-inappropriate sexual activity or touching; sexual agression with other children (especially younger or weaker ones); and physical signs. Physical signs include soreness or bleeding from the anus or genital area.
Sexual promiscuity (especially at a young age), is a big sign, as well as being anti-social, or if the child tries to hurt themselves (or ever talks of suicide). Another is if the child is scared easily, or never wants any of his or friends to come over to their house.
There are many signs of molestation. The child may be more withdrawn or nervous around strangers. You should check your child's body for signs of bruises. You can also ask the child if someone has been touching them inappropriately. If you have any suspicion that a child is being abused, you must investigate the situation.