Reproduction cost

“ In a given mating, we must take into consideration such factors as impediments to coitus, as well as those numerous agencies in the female which may interfere with the union of sperm and ovum, or with the successful implantation of the fertilized egg in the uterus, and its growth and development there till normal parturition takes place. Successful reproduction depends upon the mating of sexually sound females to equally sound males. ”

“ The ovaries, as well as all their latent germs, are remarkably influenced by the first fecundation. It seems to indicate monogamy as the rule of higher sexual reproduction. The farmer understands that if he wishes to materially improve his cows, the first offspring must be begotten by a better, purer breed, and all that follow will be essentially benefited, even if not so well sired. Neither will the best blood exhibit its most desirable qualities in the calves whose mothers have previously carried inferior stock. ”

“ This involves a diminished number of offspring, but an increased amount of time and care in the creation and breeding of each; it involves also that the reproductive life of the organism is shortened and more or less confined to special periods; it begins much later, it usually ends earlier, and even in its period of activity it tends to fall into cycles. Nature, we see, who, at the outset, had endowed her children so lavishly with the aptitude for multiplication, grown wiser now, expends her fertile imagination in devising preventive checks on reproduction for her children's use. ”

“ We are, as yet, ignorant for the most part of the causes of this lapse of fertilization. Some light has been thrown on it, however, by recent chemical experiments (the effect of sugar and other water-absorbing solutions) , in which we have succeeded in parthenogenetically developing unfertilized ova.
In the higher animals the complete maturity and development of the specific form are requisite for reproduction, but in many of the lower animals it has been observed recently that ovula and sperm-cells are even formed by the younger specimens in the larva stage. ”

“ Nature’s lavish provision of something more than 100,000 ova 50for each woman, who uses only about 500 in the course of her life, excites no little wonder. But whatever the purpose of this enormous supply, its existence makes possible the removal of all but a small fragment of ovarian tissue in cases of disease, without interference with the process of ovulation, which in turn permits reproduction. ”

“ We find in organic nature excessive production and wholesale destruction. The abundance of382 the reproductive cells in plant and animal is simply amazing. Every ejaculation in man contains two or three hundred million spermatozoa, each one of them sufficient for impregnation. Each ovary of the new-born baby girl contains about thirty thousand ova, each potentially a human being. The first effort of growth is to set aside a part of the germ itself for future reproduction, so that the germ may be indefinitely multiplied and handed down to untold generations. ”

“ Now, while Spencer was probably right in saying that fertilisation promotes change, we cannot think that he succeeded in finding what he was seeking, namely a primary physiological reason why sexual reproduction should occur. It may be pointed out that it is only in a limited sense that sperm-cells or egg-cells can be spoken of as in a state of "quiescence," and that it is only in a limited sense that the organism which has finished growing and is beginning to be sexual can be spoken of as in a state of general or molecular equilibrium. ”

“ The male, however, is much smaller, and far less developed than the female. In some of these species, germ-cells, or eggs, are found, which do not require fecundation for reproduction or development, so that they belong to the non-sexual class.
The third variety of hermaphrodites embraces those animals in which the male organs are so disposed as not to fecundate [pg 201] the ova of the same body, but require the co-operation of two individuals, notwithstanding the co-existence in each of the organs of both sexes. Each in turn impregnates the other. ”

“ The instances just surveyed, these extremes of the potentiality of procreation, are instructive in more ways than one. They are to be regarded as “excrescences” of reproduction, comparable to those “excrescences” of individual growth which we call “ornament,” for example. Individuals on whom this fertility has settled, so to speak, are the victims of the machinery of sex and reproduction. Their amazing powers of multiplication303 are not of their own seeking, they are inherent manifestations of variations of growth, uncontrollable save by the machinery of Natural Selection. ”

“ A "contraceptive" merely prevents the union of the male and female elements of reproduction, and consequently the process from which evolves the foetus or embryo. A leading medical authority has said regarding this distinction: "In inducing abortion, one destroys something already formed—a foetus or an embryo, a fertilized ovum, a potential human being. In prevention, however, one merely prevents chemically or mechanically the spermatozoa from coming in contact with the ovum. There is no greater sin or crime in this than there is in simple abstinence, in refraining from sexual intercourse." ”

“ Here, once more we see the application of the scientific axiom "Improve the environment and reproduction is checked." As Leroy-Beaulieu has said: "The tendency of civilization is to reduce the birth-rate." And as Professor Benjamin Moore has said: "Decreased reproduction is the simple biological reply to good economic conditions." And as Havelock Ellis has said: "Those who desire a higher birth-rate are desiring, whether they know it or not, the increase of poverty, ignorance, and wretchedness." ”

“ The rate of reproduction is the crux of natural selection; each species normally has such a reproduction rate as will suffice to withstand the premature deaths and sterility of some individuals, and yet not so large as to press unduly upon the food supply. The problem of natural selection is a problem of the adjustment between reproductive rate and death-rate, and the struggle for subsistence is only one of several factors. ”

“ The offspring will thus be the result of the unfolding of a bit of germ plasm which will be different from that from which either of its parents developed, and these differences will result in congenital variations. Sexual reproduction thus results in congenital variations; and if congenital variations are necessary for the evolution of the living machine—and we shall soon see reason for believing that they are—we find that sexual reproduction is a device adopted for bringing out such congenital variations. ”

“ What other reason can there be why the circuitous process of sexual reproduction has been preferred? It may be said that the arrangement by which multiplication is secured through special germ-cells, more or less apart from the cells which build up the body, may be justified as an arrangement which prevents or tends to prevent the transmission of bodily modifications, many of which are detrimental. ”

“ Fecundal selection is said by them to be constantly tending to increase the reproductive rate, because fecundity is partly a matter of heredity, and the fecund parents leave more offspring with the same characteristic. Lethal selection, on the contrary, constantly asserts its power to reduce the reproductive rate, because the reproductive demands on the parents reduce their chances of life by interference with their natural ability of self-protection. ”

“ It should be realised that all the proper, medical methods of controlling pregnancy consist, not in destroying an already growing embryo, but in preventing the male sperm from reaching the unfertilised egg cell. This may be done either by shutting the sperms away from the opening of the womb, or by securing the death of all (instead of the natural death of all but one) of the two to six hundred million sperms which enter the woman. ”

“ In the old days of unlimited fecundity, the early marriage of a beautiful, or intelligent, woman meant a probable perpetuation of her endowments; but at present, when artificial restraint of fertility is so widespread, the result does not follow as a matter of course: and it is evident that the race is little or not at all helped by the early marriage of an attractive woman, if she has too few or no children.
Fecundal selection, then, is becoming the important phase of reproductive selection, in the evolution of civilized races. ”

“ But nature is lavish where the propagation of the species is concerned. A portion of an ovary or of both ovaries might become diseased, and thousands of ova might become unfit for fertilization; nature therefore puts in an extra reserve supply. We see a still more striking example of this extreme extravagant lavishness in man; only one spermatozoön is necessary to impregnate the ovum, and only one spermatozoön can penetrate the ovum; nevertheless each normal ejaculation of semen contains between a quarter and half a million spermatozoa. ”

“ Except as determined under this Act, where a child is brought about as a result of a fertilisation procedure—
(a) the woman whose egg the child was brought about with shall not be treated as the mother of the child; and (b) the man whose sperm the child was brought about with shall not be treated as the father of the child. ”

“ As has already been said, this use of the sex organs, merely to produce progeny, and so insure a continuance of the race, is a quality that mankind shares with all the rest of the animal kingdom. In all essentials, so far as the material parts of the act are concerned, the beginnings of the new life in the human family differ not a whit from that of any other mammals. In each case the ovum is produced by the ovaries of the female, passes into the womb, is there met by the semen from the male, fertilized by the spermatozoa, and so the foetus gets its start. ”

“ This might be done by what is known as "selective fertilization" artificially with only the kind of sperm (X or Y as to chromosomes) which would produce the desired result. There is as yet no way to thus select the sperm of higher animals. It has been authoritatively claimed that feeding with certain chemicals, and other methods to be discussed later, has affected the sex of offspring. These experiments (and controversies) need not detain us, since they are not applicable to the human species. ”

“ The manner in which, in the human species, fertilization is effected, is still far from clear in all its details; hence it is easy to understand, that the etiology of sterility remains in many respects obscure. It is impossible in every case to find a definite cause. Whereas, on the one hand, notwithstanding the existence of apparently insuperable obstacles, impregnation may nevertheless be effected; so, on the other hand, sterility may exist in cases in which all the circumstances appear favourable to the occurrence of conception. ”

“ While the reproductive rate must be looked upon as a characteristic which has its adaptations like other characteristics, it has one peculiarity—its increase is always opposed by lethal selection. The chances of life are reduced by reproducing, inasmuch as more danger is entailed by the extra activities of courtship, and later, in bearing and caring for the young, since these duties reduce the normal wariness of individual life. The reproductive rate, therefore, always remains at the lowest point which will suffice for the reproductive needs of the species. ”

“ The influences in the personality of the father and of the mother, which during fertilization find expression in the qualitative constitution of the sperm and of the ovum, respectively, can thus bring about a resultant tendency, acting in one direction or the other with varying force. Thus, after fertilization, we have this resultant tendency toward the formation of a male or female embryo.
But, Düsing continues, at this time the sex is not definitely determined. The influence of the nutritive condition in which the fertilized ovum finds itself has yet to make itself felt. ”

“ The queen, it will be remembered, cohabits with the male but once in her life. The sperm-cells then received are stored in a special receptacle and are released during the passage of the egg down the oviduct. In this act of releasing the fertilizing germs a singular economy is practised. In the case of most other creatures myriads of sperm-cells are released for the fertilization of a single egg, and of these but one can possibly attain its goal, the minute aperture or “micropyle” which is the doorway to the germ liberated, in the form of an egg, by the female. The rest die. ”

“ During that brief, weird honeymoon in the clouds she received a store of spermatozoa, the fertilizing male germs, sufficient for all the eggs she can ever lay, and they may amount to nigh on a million. Incredible as this may seem, their purpose is yet more so; for they are destined to be expended solely in the production of female offspring doomed for the most part to perpetual spinsterhood. One youngster in ten thousand may attain to a higher state, may, if Fate wills, become a queen and mother. ”

“ Hence the smaller the chances of any single sperm-cell being successful, the larger is the number of such cells produced, and a direct result of this increase in number is a diminution in size. But why should the sperm-cells remain or become so large in the species in which fertilization is internal? The idea suggests itself that the species in this way gains some advantage, which must be given up in the other cases; although such advantage might consist in assisting the development of the fertilized ovum and not in any increase of the true fertilizing substance. ”

“ On the whole, then, it appears clear that no form of infertility or sterility between the individuals of a species, can be increased by natural selection unless correlated with some useful variation, while all infertility not so correlated has a constant tendency to effect its own elimination. But the opposite property, fertility, is of vital importance to every species, and gives the offspring of the individuals which possess it, in consequence of their superior numbers, a greater chance of survival in the battle of life. ”