What Will Your Child Be Like?
Will Junior be dark or fair, genius or dullard? Meet the amazing little "inner men" who make us what we are
WHAT will your child be like? Will it have its father’s eyes, its mother’s hair? Will it inherit grandfather’s musical genius—or Uncle Charley’s knack of running $10 into a million?
“What will our child be like?” The question has provided the No. 1 topic of prenatal discussion since human beings first learned to talk. Today the science of genetics the study of heredity and variation among living things can tear away much of the mystery of what characteristics we inherit and what we don’t.
It debunks the old midwives’ tale that by listening to much good music an expectant mother can enhance her child’s chances of being musical; and at the same time it assures us that some unusual
hereditary endowment is essential to produce the musical achievement of a Flagstad or a Menuhin.
It tells us that syphilis cannot be passed from father to son — but that a tendency for diabetes can.
It predicts, with reasonable accuracy, the color of your child’s hair or eyes, whether it will be short or tall, have thick lips or thin.
More than this, the heredity experts can now tell us the why of what we are. The science of genetics reveals the fascinating story of how, when man marries woman, the pair pass on to their offspring the pattern for a great multitude of characteristics many of which may not even appear in the parents, or the elements of which they themselves are unaware they possess, yet all having been passed down virtually unchanged from generation to generation.
Life’s extremely hazardous course begins when a single sperm enters a single egg. A single sperm
from all the billions produced within any man during his lifetime and as many as 500 millions of which may be released at any one time; a single egg from the hundreds stored within any woman from the moment of her own birth. And no two spermand-egg combinations are identical in the potentialities which they contain
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What Will Your Child Be Like?
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for the endowment of a new human being and a new personality.
Science has determined that within the sperm and the nucleus of the egg at the moment of conception are contained all the hereditary factors which the parents can pass on to their child. These “factors” come wrapped up in 48 rodlike packets, just barely visible under the microscope, called chromosomes half provided by the father’s sperm, half by the mother’s egg.
And here the geneticists have discovered another remarkable fact: these chromosomes are of 24 kinds as to shape, size and formation. Thus there are two of each type of packet onereceived from each parent —and the matching ones promptly pair off.
So each newly conceived life consists from the instant it begins of 24 pairs of chromosomes, and if we letter these pairs from A to X, then within this new life speck there are two A chromosomes, two B’s, two C’s, and so on. Together the 48 comprise a single cell, h^t immediately they begin to feed on the nourishment provided within the egg and by the mother. As they feed they grow and multiply.
Each chromosome splits into two, a separation takes place into two groups, each containing an identical set of chromosomes, and when the cell itself splits there are now two identical new cells. The two cells then split into four, the four into eight, to 16 . . . and the fantastic multiplication goes on into the billions. In fact it is estimated that there are 26 trillion cells in a fully developed baby.
It’s AH There
Let an expert shave a bit of skin off your finger, take a piece of your bone or a snip of your appendix, and by breaking it down into its cell structure he could show you that every cell in your body contains an exact replica of each and every one of the chromosomes with which your life began.
The chromosomes can be seen under a microscope, if treated by certain dyes to make their colorless structure visible (“chromosomes” simply means color bodies) — and the lab worker can also show you something of what these minute packets contain. At times chromosomes stretch out into longer filaments, like a string of gelatinous beads, and in these “beads” the geneticists have discovered the ultimate factors of heredity.
These basic units of life, packed inside the chromosomes, the scientists call “genes.” They are perhaps the most miraculous particles of the universe, so infinitesimally small that they cannot themselves be seen with a microscope. Scores to hundreds of them may be packeted within a single chromosome. Yet in some cases the possession of a single gene may change the whole life of an individual bar him from piloting ah airplane, because it makes him color blind . . . make him tall or short . . . give him a susceptibility to diabetes, or condemn him to an early death through the rare “bleeding disease.” hemophilia.
These genes are unique in that, though a single gene is millions of timer, j smaller than the smallest speck you can j see with your naked eye, each one is j alive. All have vital jobs to do in ' fashioning the human body and they I can reproduce themselves.
! The genes work in chain gang style. Within the A chromosome, for instance, is “chain gang A” of invisible but hefty
little workers, each one with a specificjob to do. Some are “plumbers,” who lay out the body’s intricate system of veins and arteries, others are “carpenters,” fashioning the bone structure, and “sanitary engineers” who construct the channels which carryrefuse out of the body.
But, as we have seen, in each newly conceived’ child there are two À chromosomes, two B’s, two C’s, and so on that is, there are two of each group of workers and two of each type of individual gene. Further study of this phenomenon reveals that not only are the genes alive, but in the way they labor to build our bodies they may he compared to human specialists.
Just as any two carpenters will go at the same job differently, and produce different results, the individual genes of any pair often do their mutually appointed tasks in quite different fashion. And when the two genes of any pair do differ one is generally a regular bully and the other a timid Milquetoast.
What Color Eyes?
Within every child, for instance, are two genes whose job is the laying of pigment within the iris to give the eyes their color. The “blue-eve” gene is a lazy fellow, content to provide a minimum of pigment in the rear of the iris, while the “brown-eye” gene is a brawny and industrious laborer to whom such a chore is just a start he goes on laying a heavy layer of pigment in the front of the iris as well. And if your child receives as his pair a blue-eye gene from you and a brown-eye gene from your mate, the timid blue-eye gene will hold back and let the bully-boy gene dominate the job and the child will have brown eyes.
To the scientist one is a “dominant," the other a “recessive” gene and the genetic scientists long ago discovered that timid though he is, the recessive gene in any pair makes up in patience what he lacks in determination. That blue-eye gene, for instance, won’t be able to influence the brown-eye gene a bit in coloring your child’s eyes but your son may pass the recessive gene along to his son. And if in this grandchild the timid gene should find itself paired off with another blue-eye gene, the two will work happily together to produce blue eyes.
Such a recessive gene may be passed along for several generations, always dominated by its opposite number, before it crops out again.
No chain gang of these hard-working genes is more important than those which determine sex. We have seen that within every child there are 24 pairs of gene-packed chromosomes two A chromosomes, two B’s, etc., one received from either parent. But when we get down to the end of the line we find that while there are two U’s, two V’s and two W’s, there aren’t always two X chromosomes. For, while within the mother there are two X’s, within the father this pair consist not of two X’s but of an X and a Y. Thus the child will always receive un X from the mother, but either an X or a Y chromosome from the father. Two X chromosomes will produce a girl child, an XY pair a boy.
This makes it clear that the sex of a child like the color of its eyes and hair, and a thousand other inherited characteristics is determined at the moment of conception. In ancient times, particularly in royal households, all sorts of magic potents and charms were resorted to in attempts to assure that the expectant mother would produce a male heir. But we now know that
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not even a Merlin could in any way influence sex determination or any other hereditary characteristics after pregnancy begins—and it will soon be seen that we have no such influence prior to conception either.
For it was in determining how you pass these industrious and distinctive little genes along to your children that the geneticists made one of the greatest strides in human knowledge.
Every cell in your body is an exact replica of that first cell you started with .-it the moment of conception, containing an identical set of 48 “chromosome packets” of genes. As the cells multiply, most of them set off about their specialist tasks of patterning the growth of hair, skin, muscle and so on--but one set of cells is set aside in reserve. These “reserves” are the germ cells, dedicated to posterity, from which the sperms are derived in men and the eggs in women.
Every male child at birth already has in his testes all the germ cells out of which sperms will be produced. From puberty on these germ cells begin to multiply, and continue to do so, as needed, throughout most of his life. But at certain stages, instead of going on multiplying, these germ cells and their contents divide, and each half forms sperms containing not 48 but only 24 chromosomes, or one of every pair. Because these sperms are produced without decreasing the reserve stock of germ cells, countless billions of sperms can be discharged, always leaving the original reserve cells to produce more.
In the female child a basically similar process occurs. At birth the germ cells have already divided to produce eggs, each containing 24 chromosomes, and the girl baby’s ovaries contain the tiny clusters of eggs (in rudimentary form) which will mature years later. Since normally she will be required to mature, from puberty on, only one egg a month for a period of about 35 years, the almost limitless multiplying of the germ cells is not required in the female as in the male.
Thus both the sperm and the egg contain only half the number of chromosomes required to comprise a complete new human being, and when at conception the sperm enters the egg the “magic formula” is complete. A new cell of 48 chromosomes is created, a new life begun.
But consider just what the discovery of this process means. From the instant your own life began, there were sealed away within your body all the heredity factors (or genes) which it is in your power to pass on to your own children.
If you started life with genes that tended to make you brilliant, even though sickness, laziness or hard luck have prevented you from getting an education, your children will be born with exactly the same mental equipment as if you had acquired a string of college degrees.
If you were shell-shocked or crippled during the war, your child born now will have basically the same heredity as one you might have fathered before ever you went to war.
If you are a woman, and, through disease or disfigurement, you have lost your looks, this will no more affect your child’s appearance than had you developed into a pin-up girl. And man or woman, no matter how old you are when your child is conceived, its heredita:ry make-up will be in no way altered on account of your age.
When it comes to forecasting your child’s appearance and abilities, genetic theory runs into some difficult practical hurdles. The color of your child’s hair, for instance, can be predicted with reasonable accurateness, as in the color
chart at the beginning of this article, yet even here you hit the first and greatest hazard—those timid, “hidden” genes.
If both you and your husband or wife have dark hair, and so far as you know none of your sisters, brothers, parents, aunts, uncles or grandparents had anything but dark hair, you may be reasonably certain that neither you nor your mate carry any hidden genes which would produce a lighter shade of hair. Yet. you can’t be positive but that a blond-hair gene lurks within you, so shy and retiring that it hasn’t made its presence felt for many generations. Should the same be true of your mate— bingo! You may both pass the recessive blond-hair gene to one of your children, with surprising results for the whole family connection.
On the other hand, however, if both yoü and your wife or husband are blond, all your children must also have blond hair. For the gene governing dark hair is known to be a dominant one; therefore both you and your mate must be carrying recessive blondhair genes, or else the dominant gene would have shown itself. Obviously, your children will each receive a blond gene from either parent.
The Mystery of Mutation
There is just one force at work which can actually change the genes in those “reserved” germ cells. For while nothing we ourselves can do can change them, a change called “mutation” may take place at rare intervals in any given human gene, either spontaneously or through some outside influence, as yet none too well understood. Mutation is of vital interest to humanity, because it is the fundamental force behind the long-range change, or evolution, of man and every other species of living thing. But as far as your little Willie or Caroline are concerned, you need hardly worry about that.
But something you can never forget is that going hand in hand at all times with heredity’s shy or bullying little “inner workers” as they create the new life that is your child is heredity’s complementary force — environment. And environment starts its work, like heredity, at the moment of conception.
Science today has exploded the fanciful theory that parents should “put themselves in the proper frame of mind” before a child is conceived, to assure its “inheriting” a happy disposition. We have seen that all the possible characteristics a child can inherit were determined at the moment his parents themselves were conceived. Yet serious worry or anxiety might so affect a mother’s health that her body would provide something less than the best possible nourishment for the child growing within her, once it has been conceived. If a mother smokes or drinks to excess, the nicotine or alcohol in her system may penetrate the “placenta,” which filters food to the child and protects it from most hazards before it is born, and have harmful or even disastrous effects.
A mother’s excessive use of quinine may cause deafness in a child; lead and arsenic fumes, which may be inhaled in certain factories, can be another hazard and the child of a mother addicted to the use of morphine or opium may actually be born a drug addict.
Yet none of these things can be inherited—they are the result entirely of environmental factors within the mother’s body. No more may a son directly inherit drunkenness from a drunken father, although an environment of poverty and shiftlessness, for which the father’s drunkenness may be responsible, might well lead «*on
down the same alcoholic path. A oncepuny father, who, through diet and training, developed into an outstanding athlete, may like to boast that his cupwinning son is a chip off the old block. Actually, the father’s efforts at selfimprovement before his son’s birth in no way altered the hereditary characteristics with which his son started life —the upbringing such a father would naturally provide for his son produced the young athlete.
Although it once gave rise to tremendous scientific argument, geneticists are now convinced (with the exception of perhaps one or two die-hards) that such “acquired characteristics” can in no case be passed on as inherited qualities. One simple example seems to be completely convincing: for generations, Orientals of certain classes bound the feet of their daughters, until these became quite malformed—and yet the grown daughters continued to produce children having completely normal feet.
But let’s get down to cases. There’s a baby expected at your house. The baby-blue bassinet is waiting in the nursery (it’s going to be a boy, of course!), the diapers are stored away in the new bureau drawer, the nursing bottles stand in a row on top. Everything is ready for the big event—but let’s consider for a moment the miracle that has already occurred to start this new human being—your baby—on the road to life.
First, the very special person that is going to be your child could have been the child of only two specific parents—• you and your wife or husband—out of all the billions past and present.
But, taking this for granted, consider what were the chances of this particular John Robert Brown or Mary Elizabeth Jones being conceived. Consider how many different kinds of children you and your mate could have, theoretically, if the number were unlimited.
In your germ cells there are 24 pairs of chromosomes. To any specific child you pass one chromosome of each pair, taken at random. There are precisely 16,777,216 possible combinations of 24 chromosomes which you alone may pass to your child !
But in the same random selection, your mate also passes one of every 24 pair of a different set of chromosomes to the child—another 16,777,216 possibilities.
So here’s what had to happen for your child to get its start toward birth: at precisely the right instant the one out of those more than 16 million sperms, representing the one potential half of your child, had to meet the one specific egg which held the other potential half. This could have happened only once in some 300 billion times.
On just such a miracle hung the birth of a Churchill, a Roosevelt—or a Hitler. Much more important to you at this moment, on justj such fantastic a coincidence rests the birth of the child that will be your own pride and joy—genius or dullard, beauty or ugly duckling.
And from the first instant of conception the fertilized egg that is to become your child has been an individual with all its inherent capacities already blueprinted, so far as these are determined by heredity.
Blue eyes or brown? Red hair or blond? Will it have six fingers or a tendency to diabetes? Will it live to be nine or 90?
Thousands of characteristics like these are already “in the cards,” because those amazing little “inner men” have been at work for months now, fashioning this new human life—each gene going at its particular job in a manner determined generations before you yourself were dreamed of.