Why do my kids have to fight all the time? I have three of them and they drive me crazy. Why can’t they be nice to each other?

Good question. All I can tell you is that sibling rivalry has been going on for a long time. It was responsible for the first murder on record (when Cain killed Abel), and has been represented in virtually every two-child family from that time to this. The underlying source of this conflict is old-fashioned jealousy and competition between children. Marguerite and Willard Beecher, writing in their book “Parents on the Run” ($10, DeVorss), expressed the inevitability of this struggle as follows:

“It was once believed that if parents would explain to a child that he was having a little brother or sister, he would not resent it. He was told that his parents had enjoyed him so much that they wanted to increase their happiness. This was supposed to avoid jealous competition and rivalry. It did not work. Why should it? Needless to say, if a man tells his wife he has loved her so much that he now plans to bring another wife into the home to “increase his happiness,” she would not be immune to jealousy. On the contrary, the fight would just begin — in exactly the same fashion as it does with children.”

If jealousy between kids is so common, then how can parents minimize the natural antagonism that children feel for their siblings?

It’s helpful to avoid circumstances that compare them unfavorably with each other. They are extremely sensitive to the competitive edge of their relationship. The question is not, “How am I doing?” it is, “How am I doing compared with John, Steven or Marion?” The issue is not how fast can I run, but who crosses the finish line first. A boy does not care how tall he is; he is vitally interested in “who is tallest.” Each child systematically measures himself against his peers and is tremendously sensitive to failure within his own family. Accordingly, parents should guard against comparative statements that routinely favor one child over another.

Perhaps an illustration will help make the case. When I was about 10 years old, I loved to play with a couple of dogs that belonged to two families in the neighborhood. One was a black Scottie who liked to chase and retrieve tennis balls. The other was a pug bulldog, who had a notoriously bad attitude. One day as I was tossing the ball for the Scottie, it occurred to me that it might be interesting to throw it in the direction of the old grouch. It was not a smart move. The ball rolled under the bulldog who grabbed the Scottie by the throat when he tried to retrieve it. It was an awful scene. Neighbors came running as the Scottie screamed in pain. It took 10 minutes and a garden hose to pry the bulldog’s grip loose, and by then the Scottie was almost dead. He spent two weeks in the hospital and I spent two weeks in “the doghouse.” I regret throwing that ball to this day.

I have thought about that experience many times, and begun to recognize its application to human relationships. Indeed, it is a very simple thing to precipitate a fight between people. All that is necessary is to toss a ball, symbolically, under the more aggressive of the two and prepare for the battle that ensues. This is done by repeating negative comments one has made, or by baiting one in the presence of the other. It can be accomplished in business by assigning overlapping territory to two managers. They will tear each other to pieces in the inevitable rivalry. Alas, it happens every day.

This principle is also applicable to siblings. It is remarkably easy to make them mortal enemies. All a parent must do is toss a ball in the wrong direction. Their natural antagonism will do the rest.