Kids and teens on the receiving end of sibling bullying do, indeed, experience mental distress from teasing and aggression. Interestingly, a new study found that even mild bullying — a punch once in a while — could be detrimental. “The parental reaction to a child being bullied by non-family members may be quite different from that of a sibling aggressor, which may be particularly distressing for the bullied child,” said UTMB’s Dr. Robin Mallett, a child and adolescent psychiatrist. Mallett advises parents that they “must provide developmentally appropriate supervision of children and to communicate that no bullying is acceptable, even by siblings, and that parents are available to help them with such serious matters.”