For too long, a myth has prevailed that the middle children get a raw deal. I can prove, however, that middle children occupy the most favorable position in the family, and play an essential role in maintaining world peace.

According to the myth I am about to explode, the oldest child has the advantage of receiving its parents' undivided attention for a while, before the second child is born. The youngest, on the other hand, is the last fledging who never quite clears the nest. In the family scheme, it is Ruler for Life.

As popular friction goes, the middle child is left in the least desirable position. Its birth goes comparatively unheralded, after the clamor that accompanied the arrival of the firstborn. The middle child is never the center of the family's attention, the myth says, since the oldest precedes it and the youngest is a twinkle in its mother's eye when it is born. The supposed result: The middle child is anxious and dejected.

Worst of all, middle children are apparently spreading these rumors about themselves. In "The Birth Order Factor," psychologist Lucille Forer reports that middle children "frequently complain of hardship in growing up between others." Middle children, she continues, "seem most vulnerable to maladjustment." l

For a few years after I became a middle child, I subscribed to the belief that I occupied what Forer calls "the most difficult of all birth position." I tried to turn my seeming misfortune to account by using it to make my parents feel guilty about neglecting me. I may have elicited some sympathy from my mother, who was a middle child herself.

At a tender age, I became aware that the middle-child myth was flawed. I was prodded into a closer scrutiny of the old middle-child theory by a simple observation: I was a much nicer child than my older or younger sibling.

My spindly older sister, nicknamed "Skinny Applecore" by her ruthless classmates, was a dirty trickster. Once she offered to play restaraunt with me. My suspicions should have been immediately aroused by her almost unprecedented offer to play with me, but I agreed. She promised to serve a dish called "Chocolate Delight."

Chocolate Delight turned out to be a soupy mixture of tap water and fish food, but my sister did not tell me that until I took a gulp of the swill. Then she dissolved in fits of laughter, gleefully pointing out the fish food contains such delicacies as ant larvae and mosquito eggs.

My younger brother, on the other hand, recognized even as a toddler that he exerted considerable influence over my parents. If I crossed him, he simply gasped a few times as if preparing to cry. As soon as my parents heard his "uh-uh-uh" (and he made sure they did), they would tell me to "leave him alone" without troubling to find out that I was "bothering" him by trying to stop him from throwing our puppy out the attic window.

Since I had all the meit my sister and brother lacked, I decided that a new theory about middle children was required. I soon figured out why the middle child has the best chance of growing up to be a charming human being who makes an essential contribution to world stability.

The oldest child is an experimental animal subject to all the errors made by overanxious and misguided parents. It reigns supreme for a pitifully short time, imbibing the notion that it has the center of the universe. Then, along comes the second child. The poor firstborn never recovers from the shock.

The middle child enjoys the benefits of lessons its parents learned through trial-and-error with it less-fortunate older sibling. It never has illusions that it occupies a position of central importance in the world schemes, or that it is anything but an ordinary child. Quickly, it learns that it will have to be a pleasent and easy-going if it is ever going to succeed. While the older child laments its fall from grace, the middle child acquires charm.

Along comes the baby of the family, its parents aware that they have produced their last offspring. They spoil it from the day it is born, often prolonging its babyhood for life. The child gets the idea, once shared by its oldest sibling, that it is the center of the universe. Unlike the oldest, however, the baby rarely discovers the error of this notion.

The truth is my theory is apparent to anyone who considers it objectively. Even Forer admits in her book that middle children are likely to be "more friendly and able to maintain better relationships in life."

Having established that the middle children are the best-natured people on earth, it becomes clear that middle children are the diplomats and negotiators who keep the world on a relatively even keel. Consider the middle children renowned for their tact and humanitarianism: They include Benjamin Franklin, Thomas Jefferson, John And Robert Kennedy and Susan B. Anthony.

Once the validity of my Revised Theory of the Middle Child is accepted, activities of such organizations as Zero Population Growth present an undeniable danger to world peace. ZPG encourages couples to limti their offspring to two. Although population control may have its beneficial aspects, ZPG's goal threatens to make the middle child extinct.

If they can devise a way to limit population growth without endangering my species, the world will be a better place.