Parents who have more than one child swing on a pendulum of feelings. Seeing siblings relate well to one another, spontaneously help each other, or share in a loving fashion brings exceptional joy to any parents' heart. On the other hand, when chaos erupts, and one sibling shouts "Mom, he's breathing my air!" followed by a screaming match, even the most warm hearted parent may pause to wonder why they thought having even one child would be a good idea in the first place.