Sibling rivalry is one of humanity's oldest problems. One of the first stories in the Bible (the oldest book in Western civilization, and the story of the ancient Jewish culture) deals with the rivalry between two brothers, Cain and Abel. The older brother, Cain, was irritated at constantly having to help take care of his younger brother, Abel, and kept asking his parents: "Am I my brother's keeper?" The story of these two brothers has a tragic ending; Cain becomes so angry that he kills Abel (and this, according to the Bible, was the first murder in history).
