Medicine: Twins and Worse

In the U. S. there are at least 2,000,000 people who are twins, triplets or quadruplets. The man who gets asked most about them is Geneticist Horatio Hackett Newman of the University of Chicago. In the past 25 years he has received hundreds of letters from twins, “supertwins,” parents of twins, and women who want them. They ask him all sorts of questions, “some sensible, some rather silly.” Last fortnight Professor Newman published a book on Multiple Human Births (Doubleday, Doran; $2.50) which ought to get him ahead of the questions for the next few years.

Eggs, Health, Intelligence. There are two kinds of twins: one-egg (identical) and two-egg (fraternal). One-egg twins are the result of the division of a single fertilized egg, are therefore duplicate editions of the same person. They are always of the same sex. “Two-egg twins are derived from two independent eggs fertilized by two sperms and are related to each other in exactly the same way as are ordinary brothers and sisters. . . .”

Twins lead a hazardous existence before and during birth. In the uterus they are crowded. Many are born prematurely, many are injured at birth. About one-quarter of all twins born die in the first ten days of life. “Extensive studies of twins of all ages,” says Professor Newman, “have revealed a higher frequency of mental defectives among twins than among the singly born.” But if they escape the hazards of infancy, twins “are as capable as are singly born pupils in the same schools.”

Siamese Twins are identical twins who are not completely separated. “True Siamese twins consist of two nearly complete individuals united obliquely side by side in the hip region. Internally there are two complete sets of viscera, except that there is usually a common rectum.” Their organs are symmetrical, one heart slanting to the right, the other to the left. But for some mysterious reason, they are often very unlike in facial features and personality.

There have been 13 sets of Siamese twins known to medical history. The original “Siamese” were Chang and Eng (really Chinese), born in Siam in 1811. They were taken out of Siam by a British merchant, exhibited by Circusman Barnum. After accumulating a small fortune, they married two sisters, took the name Bunker, settled down on a North Carolina farm, where they lived happily to the age of 63.

At least seven pairs of Siamese twins have been separated by surgical operation.

Chicago Fair. To study the effects of heredity and environment, Professor Newman invited to the Chicago World’s Fair ten pairs of identical twins who had been separated since infancy. In some cases they had not even met since childhood. Many had lived strikingly similar lives. “Edwin” and “Fred,” for example, both became electricity repair men, married the same year; each had a baby son and a fox terrier named Trixie.

One-egg twins with similar educations had similar mental capacities. Small differences in education had not affected this equality, but large differences did. (Dr. Newman nevertheless believes that mental growth is bounded by heredity’s limitations. “With a good education a poorly endowed person can improve his ability to a moderate degree but cannot reach the level of a potentially able but poorly educated person.”)

Dionne Quintuplets. “If a highly favorable environment could do what some psychologists claim,” says Dr. Newman, “these five children should be far ahead of most children of their age in mental development [but] the quints are all somewhat retarded mentally … a disappointing mediocrity, to say the least.”

Dr. Newman makes some excuses for the quints: 1) they were born prematurely; 2) “They have but little use for spoken language. All their wants are anticipated and all their activities are scheduled”; 3) they have no playmates, have nothing to say to each other; 4) their parents, according to Dr. Newman, “exhibit nothing exceptional in the way of mentality.” In spite of these handicaps the quints are “good, normal human beings of almost average mental ability.”

“As a setup for determining the relative shares of hereditary and environmental factors the whole arrangement as it now stands is about as poor as it could possibly be made.” The quints, says Dr. Newman, should be given different environments, since they are identical, have exactly the same heredity patterns.