CAIN MARRIES A SISTER

In primitive societies it is a general rule that brothers do not marry their sisters. The strictest of taboos are applied to this particular form of incest. Yet, from certain points of view, close inbreeding -- especially within a family of prominence -- has something to commend it when considered from the social and economic point of view: both material wealth and wealth in the form of rights or privileges are by this means kept closely within the family. An excellent example of this was to be found among the Incas, where the right to marry within the clan, and indeed to any who were first degree relatives, was reserved for the chiefs primarily to protect the interests of the royal house. According to Felip Huaman Poma de Ayala in his El Primer Nuevo Chronica Y Buen Gobierno, published in Paris in 1926, the formal Inca statement was: ⁽¹⁾

We, the Inca, order and decree that no one shall marry his sister or his mother, nor his first cousin, nor his aunt, nor his niece, nor his kinswoman, nor the godmother of his child, under penalty of being punished and of having his eyes pulled out . . . because only the Inca is allowed to be married to his carnal sister. . . .

In "modern" times the maintenance of rights within a family by this means is best exemplified in the royal families of Europe, the right in this instance being the right of holding dominion rather than material wealth per se -- since many royal families are impoverished. But as is well illustrated in the case of the Spanish royal family, close inbreeding has had a very deleterious effect. Charles Blitzer, writing of this family, spoke of Charles II in the following way: ⁽²⁾

Charles II of Spain, the most grotesque monarch of the seventeenth century, had been a travesty of a king. Generations of royal intermarriage had culminated in Charles in a creature so defective in mind and body as to be scarcely even a man. He was born in 1661, the product of his father's old age, and his brief life consisted chiefly of a passage from prolonged infancy to premature senility.

He could not walk until he was ten, and was considered to be too feeble for the rigours of education. In Charles, the famous Hapsburg chin reached such massive proportions that he was unable to chew, and his tongue was so large that he was barely able to speak.

Lame, epileptic, bald at the age of 35, Charles suffered one further disability, politically more significant than all the rest: he was impotent.

The Medici family -- beginning with Giovanni di Bicci de Medici (1360-1429) and ending, in one line, with Catherine de Medici (1519-1589) who married Henry II of France -- provides us with another instance where inbreeding clearly affected viability.   The members of the family for successive generations traced through two lives lived shorter and shorter, with the notable exception of Catherine herself.   These two lines are given below with their life spans indicated by years rather than dates, to simplify the figures ⁽³⁾.

Other branches of the family seemed to have done very much better, a fact which suggests that marriages further afield led to the birth of quite normally viable offspring.

While it is customary to assume that close inbreeding has always a damaging effect, this is not strictly true -- as is evident in the case of the Inca rulers, whose royal prerogative it was to marry sisters. Indeed there could conceivably be a connection between a ruling house and incestuous marriage, for genetic reasons. In antiquity and during periods when ruling houses were first establishing themselves, only such families as produced a line of particularly energetic and forceful individuals would be likely to come to power. It might very well be evidence of exceptional breeding (in the genetic sense) that a line could survive the potential hazards of inbreeding such as are involved in a series of brother-sister marriages. That a particular "house" could so inbreed successfully might quite rightly establish that house as an exceptional one from the genetic point of view. A Royal House may therefore have been any house which could successfully mate in this incestuous way and not witness any ill effects, while at the same time accumulating and consolidating its wealth and prestige.

At any rate, the Incas were a notable royal house and certainly practiced incest over a considerable number of generations without ill effect. As Murdock said: ⁽⁴⁾

The long line of Inca emperors reveals only one man of mediocre talents; all the rest displayed exceptional energy, resourcefulness, tolerance, and magnanimity in the conduct of affairs. Certainly no dynasty with a higher average order of capacity has graced a throne in the whole of human history.

It is well known that the Ptolemies also married their sisters in order to maintain the integrity of material wealth and rights, and the experiment was not without success if Cleopatra is any indication. This notable woman represented the seventh generation of such brother-sister marriages. There is some evidence, I believe, that her young brother was showing signs of mental deficiency, a circumstance which, if it is true, might be an indication that the inbreeding process was just beginning to break down and the line was at the end of its genetic good fortune.

Other royal families, the Alii among the Hawaiians, for example, and the Singhalese ⁽⁵⁾ must be counted among those who practiced this principle of brother-sister marriages. Against this background one may remember that among the common people such marriages were taboo. Primitive people are highly observant and quickly learn to avoid doing things which reduce the viability of their community as a whole. Experience taught these that the children of brother-sister matings were in one way or another apt to be less healthy than the children of those who married more distant relatives.

But it seems likely that these people also observed rather quickly that the wealth of a family was dissipated when the various children married at too great a distance in terms of blood relationship. Hence almost all such people laid down rules which, while forbidding marriage to a brother or a sister, also frowned on marriage to anyone who was only remotely related; in the latter case, the bride price paid by the groom or the dowry brought by the bride tended to pass out of the family's control. They therefore bracketed the range of relationship within which one might marry, avoiding the extremes. Indeed, in most cases the relationship considered ideal was the marriage of cousins, a practice almost universal among primitive people.

Now, the judgment made by the general public in such a case might very well have been firmly founded upon fact: namely, such a family was, in their genetic makeup, truly an outstanding one. This observation makes perfectly good sense when it is realized that through the centuries we have accumulated individually so much low-grade genetic material that when brothers and sisters marry, the same particular kind of low-grade material finds expression in the offspring in a reinforced way, in a way which will be examined a little more fully subsequently; the end result is that such children are apt to be much below average in many different ways. As we shall show, experience fully bears this out, and theory has reached such a point of refinement that geneticists can often predict quite accurately the degree of probability of detrimental traits that will appear in such children. Thus, when brothers do marry sisters without such deleterious effects, we have to all intents and purposes good evidence that quite by chance they have inherited a less damaged genetic constitution.

Although I do not have available all the information that would be required to substantiate what I wish to propose below, I think we may well have in recent times a good illustration of these general principles. I have in mind a very primitive people in South India known as the Toda, ⁽⁶⁾ who practice polyandry -- that is, several men (normally brothers) share one woman who becomes wife to them all. In writing of these people, George Murdock referred to them as a "race of superb men and hideous women." Elie Reclus, in his work on comparative anthology titled Primitive Folk, also refers to the splendid character (within the context of their culture) of Toda males. And he added this remark, which is apropos: ⁽⁷⁾

Marriage between relatives has had no dire consequences in this tribe, which, though it has practiced the closest endogamy (marriage within the family) for centuries, possesses an athletic constitution and pleasing exterior, and is famed for the gentleness of its manners, and the peacefulness and tranquillity of its way of life.

Although toward the end of the last century the Toda were apparently beginning to decline as a consequence of their contact with more highly civilized people and the breaking up of their own native customs, we have sufficient evidence from the studies of W. H. R. Rivers and others that close intermarriage had not proved detrimental to these people in the way that it habitually does among other peoples, whether primitive or highly civilized. Some fortuitous circumstance had therefore preserved among these people a genetic strain less damaged with the passage of time than most of us share. It is apparent, therefore, that not only so-called royal families but even whole tribes may closely intermarry with impunity upon certain occasions, while others cannot do so without disastrous results.

Let us therefore examine the factors which determine when brother-sister marriages will be harmful and when they will not: and in what form the degeneration is likely to show up. And let us consider why this effect results. It will be necessary to attempt to do this without becoming too involved in the jargon of the geneticists; thus some statements may be somewhat unsatisfactory from the point of view of the experts, an ever-present danger when oversimplification is required.

1. Felipe de Ayala: quoted by Victor W. von Haggen, Realm of the Incas, Mentor Books, New York 1957, p.125
2. Blitzer, Charles; "The Age of the Kings," in Great Ages of Man, Time Inc., New York, 1967, p.168.
3. Hale, John R, "The Renaissance," in Great Ages of Man, Time Inc., New York, 1965, p.165.
4. Murdock, George P., Our Primitive Contemporaries, Macmillan, New York, 1951, p.417.
5. Alii of Hawaiians: according to Dr. Gorden Brown, Dept. of Anthropology, University of Toronto; Singhalese: Edward B. Tylor, Primitive Culture, Murray, London, 1891, vol. 1, p.50.
6. Murdock, George P. ref. 4. p.106.
7. Reclus, Elie, Primitive Folk: Studies in Comparative Ethnology, Scott, London, no date, p.200

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