Originally reproduction is a part of the function of all protoplasm; and in the primitive life-forms an individual becomes two by the "simple process" of dividing itself into halves. Had this method continued into the higher forms most of the trouble as well as most of the pleasure of human existence would never occur. Or had the hermaphrodite method of combining two sexes in the one individual, so frequent in the plant world, found its way into the higher animals, the moral struggles of man would have become simplified into that resulting from his, struggles with similar creatures. Literature would not flourish, the drama would never have been heard of, dancing and singing would not need the attention of the uplifter, dress would be a method of keeping warm, and life would be sane enough but without the delicious joys of sex-love.
Why are there two sexes?[1] I must refer the reader to the specialists in this matter, but can assure him that no one knows.
With the rise of Mandel's theory of heredity, it has been assumed that such a scheme offers a wider variety of possible character combinations. At present it is safe to say that no one can give a valid reason for the existence of male and female, and that while this elaboration of the reproducing individual into two parts may be necessary for some purpose, at first glance it appears like an interesting but mysterious complication.
[1] See Lloyd Morgan's book on sex.
I refer the reader to textbooks in anatomy and embryology, and to the specialists on sex like Krafft-Ebbing, Havelock Ellis and Ploss for details as to the differences between man and woman.
There are first the essential organs of generation, differing in the two sexes, the ovary furnishing the egg, the testes furnishing the seed or sperm; then the organs of sexual contact; the secondary sex characteristics, such as stature, distribution of hair, deposits of fat, shape of body and especially of the pelvis, the voice, smoothness of skin, muscular development, etc.
There is an orderly evolution in the development of sex characters which starts with earliest embryo life and goes on regularly until puberty, when there is an extraordinary development of latent characters and peculiarities. After puberty maturity is reached by easy stages, and then comes involution or the recession of sex characters. This is reached in woman rather suddenly and in man more gradually. The completely differentiated man differs from his completely differentiated mate in the texture of his hair, skin, nails; in the width and mobility of pupils, in the color of his sclera, etc., as well as in the more essential sex organs.
Indeed there are very essential bodily differences that are obviously important though not well understood. One is that the bodily temperature of man is slightly higher than that of woman, and that he has five million red blood corpuscles to every cubic millimeter of his blood, while she has four and a half million; that his brain weighs considerably more but is not heavier proportionately; that her bodily proportions resemble those of the child-form[1] more than do his, which some interpret as a point of superiority for her, while others interpret it as a sign of inferiority. On the whole, the authorities consider that man is made for the discharge of energy at a high rate for a short time, he is the katabolic element, while woman stores up energy for her children and represents the anabolic element of the race.
[1] See Havelock Ellis.
As a corollary to the above, it is necessary to know that each human being (and also each higher animal) starts out with the potential sex organs of both sexes, and that each individual becomes sexually differentiated at about the eleventh week of intra-uterine life. Moreover every male has female organs, and every female has male organs, though in the normal conditions these are mere vestiges and play no part in the sex life of the person. Yet this indicates that the separation of male and female is not absolute, and logically and actually a male may have female characters, physically and mentally, and vice versa a female may resemble the male in structure and character.
The sex relations have in the racial sense reproduction as their object, but it is wise to remember that in the whole living world only man knows this, and he has known it for only a relatively short time. Furthermore, in youth, when the sexual life is at its intensest, this fact, though known, is not really realized, and in the individual's plans and desires parenthood figures only incidentally, if at all. Society, in its organization, places its emphasis on child-bearing, and so indirectly reproduction becomes a great social aim rather than an individual purpose.
