"Parents tend to think that sibling violence is "sibling rivalry" and is just a normal part of growing up. They fail to understand that kids can only tolerate so much demeaning before a "kick-the-dog" syndrome sets in. In other words, Colin had nowhere else to take his anger except to his sibling. I asked him if he thought about telling his parents to intervene. His response was very typical: "No, I don't think they could do anything. I was also worried it might get worse. Also some of the bullies were my friends." This last sentence tends to perplex parents. Bullied by friends is a concept that does not seem to compute. However this is exactly what happened to Colin, and it happens to many kids."