The term “The Determination of Sex” is employed in two general senses in scientific circles.
The first usage is that of the biologist, and it includes within its scope merely the discovery and understanding of the causes which determine whether the embryo shall develop into a male or into a female. In the discussion of the subject from this standpoint there is but little, if any, attention given to the question of whether the sex of the unborn child may be determined by methods under the control of man. The biologist simply studies the causes which seem to lead to the production of an individual of one or the other sex, without regard to whether these causes, when discovered, may or may not be amendable to human control.
An authority, speaking of this standpoint concerning the question referred to, says: “We may discover the causes of storms or earthquakes, and when our knowledge of them is sufficiently advanced we may be able to predict them as successfully as astronomers predict eclipses, but there is little hope that we shall ever be able to control them. So it may be with sex; a complete understanding of the causes which determine it may not necessarily give us the power of producing one or the other sex at will, or even of predicting the sex in any given case. Whether we shall ever be able to influence the causes of sex-determination cannot as yet be foretold; at present, biologists are engaged in the less practical, but immensely interesting, problem, of discovering what those causes are.”
The second usage of the term, includes and embraces the idea of the voluntary determination or control of the sex of the future child, by means of certain methods or certain systems of treatment, etc. Of recent years, science has been devoting considerable attention to the question of whether or not man may not be able to produce any particular sex at will, by means of certain systems or methods of procedure. Many theories have been evolved, and many plans and methods have been advocated, often with the expenditure of much energy and enthusiasm on the part of the promulgators and their adherents.
In this lesson there will be briefly presented to you the general consensus of modern thought on the subject, with a general outline of the favorite methods and systems advocated by the several schools of thought concerned in the investigation.
Professor Doncaster, the well-known authority on the subject, says: “But little progress has been made in the direction of predicting the sex of any child, and, if possible, even less in artificially influencing the determination of its sex. When the general principles arrived at are borne in mind, it must be confessed that the prospects of our ever attaining this power of control or even of prediction are not very hopeful, but the possibility of it cannot be yet regarded as entirely excluded. The general conclusions arrived at are that sex is determined by a physiological condition of the embryonic cells, that this condition is induced, at least in the absence of disturbing causes, by the presence of a particular sex-chromosome. [A “chromosome” is a portion of the chromatin, or substance characteristic of the nucleus of the cell, this nucleus seemingly controlling the life-processes of the cell.] But there is evidence, which for the present at least cannot be neglected, that certain extraneous conditions acting on the egg or early embryo may perhaps be able to counteract the effect of sex chromosome.
“Quite generally, then, there are two conceivable methods by which the sex might be artificially influenced in any particular case; firstly, if means could be found of ensuring that any particular fertilized ovum received the required chromosomes; and, secondly, by the discovery of methods which always effect the ovum or embryo in such a way as to produce the desired sex. Many suggestions for applying both methods have been made, some of which have attained considerable notoriety, but hitherto none of them has stood the test of practical experience. In the case of the higher animals, especially of the mammals, in which the embryo develops in the maternal uterus until long after the sex is irrevocably decided, it is obviously difficult to apply methods which might influence the sex after fertilization, even if it were certainly known that such methods were ever really effective.
“Apart from the few experiments like those of Hertwig on rearing tadpoles at different temperatures, there have been a very few cases in which there is even a suggestion that the sex of the fertilized egg can be modified by environment, and the belief that this is possible has been entirely abandoned by many of the leading investigators of the subject. It is probable, therefore, that if it will ever be possible to predict or determine artificially the sex of a particular child, the means will have to be sought in some method of influencing the output of germ-cells in such a way that one kind is produced rather than the other. It is in this way that Heape and others interpret the results of their investigations; they find that certain conditions affect the sex-ratio of cells, and they explain the result by assuming that under some circumstances male-determining ova are produced in excess, and under other circumstances, female-determining.”
Professor Rumley Dawson holds to the opinion that the male-determining and female-determining ova are discharged alternately from the ovaries. In woman one ovum is usually discharged each month, and it is maintained that on one month the ovum is male-determining, and in the next, female-determining. It is obvious that exceptions must occur, for boy and girl twins are quite common, but if the cases which support the hypothesis are taken by themselves, and the exceptions explained away, it is possible to make out a strong case in favor of this theory. Some authorities hold that the right ovary produces male-determining ova, and the left ovary female-determining, and that the two ovaries discharge an ovum alternately, but an impartial examination of the evidence for this belief shows that it rests on very slender foundations. Experiments on the lower animals have shown that after the complete removal of one ovary the female may produce young of both sexes. Women, also, have produced children of a particular sex after the corresponding ovary has been removed, and it is hardly possible to believe that the removal in all these cases was incomplete. On the whole it must be concluded that the theory is insufficiently supported by the evidence.
Another widely promulgated and vigorously supported theory is that which holds that the sex of the future child may be determined by specific nutrition of the mother before conception, and in some cases after conception. Schenk’s theory, advanced about 1900, attracted much attention at the time. He based his method on the observation that a number of women whose children were all girls all excreted sugar in their urine, such as happens in the case of persons affected with diabetes. From this he suspected that the physiological condition which leads to the excretion of sugar was inimical to the development of male-determining ova, and that males could be produced by its prevention. He therefore recommended that those who desire a male child should undergo treatment similar to that prescribed for diabetes for two or three months before conception, and held that a boy would be produced by these methods. Although this method has had considerable vogue, it cannot be held to have been established on a scientific basis.
Doncaster says “The general conclusion with regard to man must therefore be that if sex is determined solely by the spermatozoon there is no hope either of influencing or predicting it in special cases. On the other hand, there is considerable evidence that the ovum has some share in the effect, and if this is so, before any practical results are reached it will be necessary to discover which of two conceivable causes of sex-determination is the true one. It is possible that there are two kinds of ova, as well as two kinds of spermatozoa, and that there is a selective fertilization of such a kind that one kind of spermatozoon only fertilizes one kind of ovum, the second kind of spermatozoon the second kind of ovum. If this should prove to be the case, it is possible that means might be found of influencing or predicting that kind of ovum which is discharged under any set of conditions. Secondly, it is possible that the ova are potentially all alike, but that their physiological condition may under some circumstances be so altered that the sex is determined independently of the spermatozoon. * * * It is hardly possible to avoid the conclusion that the sex of the offspring may be influenced, at least under certain circumstances, by the mother. The search for means of influencing the sex of the offspring through the mother is not of necessity doomed to failure. No results of a really positive kind have been obtained hitherto, and some of the facts point so clearly to sex-determination by the male germ-cell alone in man and other animals that many investigators have concluded that the quest is hopeless; but until an adequate explanation has been given of certain phenomena discovered in the investigation of the subject, it seems more reasonable to maintain an open mind, and to regard the control of sex in man as an achievement not entirely impossible of realization.”
Another writer on the subject has said: “Every individual among the higher animals, whether male or female, begins as an impregnated ovum in the mother’s body. Any such ovum contains elements of constitution from both of its parents. In the earliest existence of this impregnated ovum, there is a season of sexual indifference, or indecision, in which the embryo is both male and female, having the characteristic rudiments of each sex, only indifferently manifested. In this stage, the embryo is susceptible of being influenced by external conditions to develop more strongly in the one or the other direction and thus become distinctly and permanently male or female. It is evident that this is the season in the development of the individual in which influencing conditions and causes must operate in deciding its sex, although it is possible in some of the lower animals to alter the tendency of sex in the embryo from one sex to the other, even after it has been quite definitely determined. It is well established, in fact, that differences do not come from a difference in the ova themselves; that is, there is not one kind of ova from the female which becomes female, while other ova become male, for it is possible to alter the tendency toward the one sex or the other after the ovum has been fertilized and the embryo has begun its career of development. This possible change in sex tendency in the embryo also proves that sex is not decided by a difference in the spermatozoa; that is some of the sperm cells from the father are not male, while others are female, in their constitution.
“It is incorrect to suppose, as has been held by some theorists, that one testicle give rise to male spermatozoa and the other to female spermatozoa, for both male and female offspring have been produced from the same male parent after one testicle or the other has been removed. The same is true in cases in which either ovary has been removed from the mother; that is, male and female offspring are produced from mothers in whom either ovary has been removed. In like manner, the sex of offspring is shown not to be materially affected by the comparative vigor of the parents; thus, a stronger father than mother does not necessarily produce one sex to the exclusion of the other. These negative decisions are important because they simplify the solution of the problem of sex-determination, by excluding, more or less fully, various causes which have been supposed to operate quite forcibly in deciding the sex of offspring. Some of the more positive agencies that enter into the determination of sex are found (1) in the influence of nutrition upon the embryo during its indifferent stage of sexual development, and (2) in the constitution and general condition of the mother before and during the early stages of pregnancy. These two factors appear to enter more fully than any others in the decision of the sex in offspring, and deserve the greatest consideration. The influence of food in supplying the embryo with nourishment for its development is, perhaps, the most potent of these determining causes.”
Investigators along the line of theory indicated in the above last quotation, i. e., the theory of sex determination by means of nourishment of the mother and embryo, have presented a volume of reports which demand respectful consideration. The general report may be said to be the discovery that abundant nourishment during the period of sexual neutrality tends to produce females; while lack of abundant nutrition during such period tends to produce males.
These experiments, of course, have been chiefly performed upon the lower animals. The frog has been a favorite subject of such experiments—the tadpole stage being the one selected, because in that stage there exists a lack of sex, the stage being one of sex neutrality. Professor Yung’s celebrated experiments will illustrate this class of experiments. Here were chosen 300 tadpoles, which when left to themselves manifested a ratio of 57 prospective females to 43 prospective males. These were divided into three classes of 100 tadpoles each. Each class was then fed upon one of several kinds of nutritious diet in order to ascertain the change in sex-tendency due to such food. The first set, with an original ratio of femaleness of 54 to 46, were fed abundantly on beef, and the ratio of femaleness was changed to 78 to 22. The second class, with a ratio of femaleness of 61 to 39, were fed on fish (specially nourishing to frogs), and the ratio changed to 81 to 19. The third class, with a ratio of 56 to 44, were fed upon a still more nutritious diet (i. e., that of frogs’ flesh), and the ratio was raised to 92 to 8. In short, the experiments showed that the increase of nourishment in diet changed every two out of three male-tendency tadpoles into females. The experiment was held to prove that a rich diet, affording nourishment, during the period of sexual neutrality in the embryo, tended to develop femaleness.
The advocates of this theory also point to the instance of the bees. With the bees, the larva of ordinary worker-bees are fed ordinary food, and do not develop sex; while the larva which is intended to produce the queen-bee is fed specially nutritious “royal food,” and consequently develops larger size and full female sex powers. If the queen is killed, or dies, the hive of bees proceeds to produce a new queen by means of feeding a selected larva with the “royal food” and thus developing full femaleness in it. It is said by some authorities that in cases in which some other of the larva accidently receive, through mistake, crumbs of the “royal food,” they, too, grow to an extraordinary size, and develop fertility. This fact is held by the advocates of the nutrition theory to go toward establishing the fact that abundant nourishment of the embryo, during the neutral stage, tends to produce femaleness in it. They also claim that caterpillars which are very poorly nourished before entering into the chrysalis stage usually develop into male butterflies, while those highly nourished in the said stage tend to become females. Experiments on sheep have shown that when the ewes are particularly well nourished the offspring will show a large proportion of females.
A writer, favoring the theory in question, says: “In general, it is reasonable to infer that the higher sexual organization which constitutes the female is to be attained in the greatest number of cases by embryos which have superior vital conditions during the formative period. Among human beings, some facts of general observation become significant in the light of the foregoing inferences. After epidemics, after wars, after seasons of privation and distress, the tendency is toward a majority of male births. On the other hand, abundant crops, low prices, peace, contentment and prosperity tend to increase the number of females born. Mothers in prosperous families usually have more girls; mothers in families of distress have more boys. Large, well-fed, fully developed, healthy women, who are of contented and passive disposition, generally become mothers of families abounding in girls; while mothers who are small or spare of flesh, who are poorly fed, restless, unhappy, overworked, exhausted by frequent childbearing, or who are reduced by other causes which waste their vital energies, usually give birth to a greater number of boys. As a general proposition, the facts and inferences tend to establish the truth of the doctrine with women, that, the more favorable the vital conditions of the mother during the period in which the sex of her offspring is being determined, the greater the ratio of females she will bear; the less favorable her vital conditions at such times, the greater will be her tendency to bear males. That many apparent exceptions occur does not disprove the general tendency here maintained. Moreover, it is impossible to know in all cases what were the conditions of the mother’s organism at the time in which her child was in its delicate balance between predominant femaleness and maleness; else many cases which seemingly disprove the proposition would be found to be forcible illustrations of its truth. Still further, it is probable that other causes besides those here mentioned act with greater or less effect in determining the sex of offspring.”
Based upon this general theory of the relation of nutrition to sex-determination, many methods and systems have been devised by as many authorities, and have been followed and promulgated by as many schools. Without going into the almost endless detail which would be necessitated by a synopsis of these various methods and systems, it may be said that they all consist of plans having for their object the decrease of nutrition of the woman in cases in which male children are desired, and the increase of nutrition in cases in which female children are sought for. This increase or decrease in nutrition is enforced for a reasonable period before the time selected for the conception of the child, and also for a reasonable period after the time of conception. The decrease in nutrition does not consist of “starvation,” but rather of a “training diet” similar to that followed by athletics, and from which dietary all rich foods, sweets, etc., are absent. In fact, the average dietary advocated by the “Eat and Grow Thin” writers would seem to be almost identical with that of the “male offspring” theorists.
Many persons who have followed the methods and systems based on the nutrition theory above mentioned claim to have been more or less successful in the production of the particular sex desired, but many exceptions to the rule are noted, and some writers on the subject are disposed to regard the reported successes as mere coincidences, and claim that the failures are seldom reported while the successes are widely heralded. The present writer presents the claims of this school to the attention of his readers, but without personally positively endorsing the idea. He is of the opinion that the data obtainable is not as yet sufficient to justify the strong claims made for the theory in some quarters; but, at the same time, he does not hesitate to say that there are many points of interest brought out in the presentation of the theory, and that many thoughtful persons seem to accept the same as reasonably well established and logical.
Another theory which has been heard of frequently of late years is that in which it is held that the ova are expelled in alternating sex, each month. Thus, if a male ovum is expelled in January, the February ovum will be a female one, according to this theory. Under this theory if the date of conception of a child be ascertained, and the sex of the child noted at its birth, it is a simple matter to count forward from the menstrual period following which the child was conceived, and thus determine whether the ovum of any succeeding period is male or female. It should be noted, however, that the periods are regulated by the lunar months, and not the calendar months. The fact that twins of different sexes are sometimes born would seem to disturb this theory—but not more than any other theory of sex-determination voluntarily produced, for that matter. The several schools explain this apparent discrepancy by the familiar saying that “exceptions prove the rule.”
Another theory of sex-determination is that which holds that when conception occurs within a few days after the last day of menstruation, the child will be a girl; and that when conception occurs at a later period, the child will be a boy. Methods and systems based upon this theory are also reported as being reasonably successful in producing satisfactory results. But, inasmuch as there appears to be a great difference in individual women in this respect (even according to the claims of this school of sex-determination), it would seem that it would be difficult to proceed with certainty in the matter in most cases. One of the writers advocating this method, says: “Conception within five days after the end of the menstrual period is almost certain to produce a girl child; within five days to ten days, it may be either a boy or a girl; from ten to fifteen days, it is almost sure to be a boy; from eighteen to twenty-five days is the period of probable sterility, in which conception is extremely unlikely to occur.”
In conclusion, it may be said that Nature undoubtedly has certain rules of sex-determination which govern in these cases; and that it is possible if not indeed probable that these rules may some day be discovered by man, and turned to account; but that it is very doubtful whether the secret has as yet been solved by the investigators. The writer may be pardoned for suggesting that, in his opinion, if the discovery is ever made it will likely be found to be very simple—so simple that we have probably overlooked it because it was in too plain sight to attract our attention. Nature’s methods are usually very simple, when once discovered. She hides her processes from man by making them simple, it would seem.
PRIVATE Sex Advice to Women By R. B. Armitage, M. D.
For Young Wives and those who Expect to be Married.
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