The American Red Cross defines sibling rivalry as the jealousy, competition and fighting that breaks out between brothers and sisters over everything from toys to attention. Sibling rivalry is common. It can swing back and forth from fighting to getting along well with each other. Though it may be hard to believe, sibling rivalry can even have a positive side. Working things out with their siblings gives children a chance to develop important skills like getting along with others and being able to see another person’s point of view.