If your children could inherit cancer, should you have children?
If your children could inherit cancer, should you have children?
AT YOUR SERVICE
IF YOU SUFFER FROM diabetes, varicose veins, short sight, or any one of several hundred other assorted ailments, it’s your fault for not choosing your parents more carefully. More accurately, it’s your parents’ fault for putting together your particular assortment of genes when they formed a reproductive team.
Of course, genes — those ultramicroscopio particles in our cells that determine heredity -— are the last thing most loving couples think about when under the compelling spell of the great passion. But geneticists are becoming more insistent in their warnings that this sort of preoccupation with posterity has to come.
Dr. H. Bentley Glass, retiring president of the American Association for the Advancement of Science, one of the world’s leading geneticists, rounded off his farewell address to the annual meeting in December by predicting that in the foreseeable future no parents will have the right “to burden society with a malformed or mentally incompetent child.” Couples with a family history of such defects will be required to seek an abortion if the woman becomes pregnant, he said. “This type of regulated society will be inevitably forced upon us . . . the once sacred rights of man must change in many ways.” The alternative for such potential parents will be adoption.
In fact, until quite recently, carefree — and perhaps careless — parents were hardly to blame for not knowing how they can predestine their children’s health. Although your parents threw your genes together in what may seem rapturous abandon, they didn’t know any better. It’s only 15 years ago that the correct number of chromosomes — rod-shaped bodies in the cell that carry the genes — in man (46) became known. It’s only 12 years ago that a defect in chromosomes was definitely identified as the cause of disease. But, since then, discoveries in the field of genetics have been so dramatic in solving mysteries unexplained by the effects of infection and nutrition that the new science is fast becoming a major part of medicine. The major ailments that
have now been linked to a bodily legacy passed on from your ancestors are:
Diabetes: the most common form of this disease is diabetes mellitus (the word mellitus means honeylike and refers to the sweetness of the urine). The predisposition to diabetes is governed by a gene that may be passed on to the child by only one parent. Since about one quarter of the population carries this gene, it is quite common for a diabetic to marry a carrier. When this happens, the chances of their children being diabetic are about one in seven. Now that insulin allows diabetics to live almost normal lives, more of them reach adulthood, marry and have children. This illustrates how modern medicine thwarts nature’s fail-safe mechanism: in man, the survival of the fittest no longer applies.
Heart disease: a family history of coronary trouble doesn’t condemn you to a heart attack. But you may have an inherited disposition to high blood pressure, high blood cholesterol, or other conditions that make a heart attack more likely. If you know the risk, you'can improve the odds by exercise, weight control, diet, together with regular checkups by a physician who is alerted to your family’s medical history.
Heart defects: these are another matter. While not all heart defects found in newborns are hereditary, there may be a genetic link. In this case, the risk of passing similar defects on to children is greater. Here again, many babies who would once have died are now being saved by modern heart surgery. They survive and grow to reproductive adulthood. The odds are about one in 50 that one of their children will be born with a heart defect. Not forbidding figures, but worth bearing in mind.
Rheumatic disease: this is another area where the new genetic theories could provide the answer to a lot of riddles. Only gout has so far definitely been proved to be influenced by heredity, but rheumatoid arthritis and osteoarthritis are now considered strong suspects.
Cancer, or more precisely the whole group of diseases called malignancies, has some genetic overtones. Breast cancer is twice as likely in a woman if her sister or mother had it. The same is true for men and women in other specific sites such as the stomach, uterus or prostate. Some of the increased risk may be due to a shared environment, or even diet, but heredity seems to govern the predisposition to some malignancies.
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Structural defects such as varicose veins, short sight and even protruding ears are brought about by the passing on of genes that control the shape and function of the organs involved.
Some serious diseases of the nervous system are ' hereditary, although mercifully rare. Tay-Sachs disease, which affects infants in Jewish families, is now being intensively studied in Canada as part of the fast-growing movement to learn more about genetics. It causes blindness in affected babies, together with insanity and death before the age of three.
The risk of having a child affected by an inherited disease has been precisely calculated by genetic statisticians. If a parent has a dominant trait (which need be passed on by only one parent to affect the child) the risk is one in two. This should be enough to deter most parents from taking the chance if the defect is serious. Where a recessive gene is involved (meaning that both parents must contribute an affected gene) and there is already one child affected, the risk of the next child inheriting the defect is one in four. The calculations get more complex, according to the genes involved and the number of children already born.
The new science of genetics is both a burden and a boon to any responsible young couple planning a family. It’s worth asking relatives about the family health history on both sides. If there’s any pattern of recurrent trouble, talk it over with your family physician. He can, if necessary, direct you to the genetic counseling services now available in most major cities.
But for those of us who have arrived, sd to speak, what can be done about the genetic cards we’ve drawn? Not much, other than to be aware of any potential risks, including allergies. If, for example, great grandpa was violently ill after eating oysters, and your mother’s uncle daren’t touch scallops, you might be wise to pass up clam chowder. □
ANSWER: ACROSTIC NO. 7
JOHN M. ROBSON The Hmnnn Retort
There was a major complaint about the size of the student body. There were, for example, repeated laments about one brute who has scarred several members of the teaching staff, and it was universally agreed that she should be Waterlooed or Lakeheaded.
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