Add Yahoo as a preferred source to see more of our stories on Google. My little sister is my best friend. My mother often compares us to the March sisters from Little Women, and whenever we get ...

Eighty percent of U.S. children have a sibling. Siblings can be sources of companionship, play, and joy—as well as jealousy, rivalry, and aggression. A national survey found that one-third of U.S.