The ignorance of parents in relation to essential facts is deplorable. I believe it to be the source of our gravest social evils. In the present work, therefore, which I offer to my profession as an aid in the instruction of parents and guardians of the young, I shall speak with the frankness of profound respect in relation to our God-created faculties. As a Christian physiologist, I shall endeavour to show the true and noble use involved in the highest of our human functions.

CHAPTER I
The Distinctive Character of Human Sex

A fundamental error as to the nature of human sex too generally exists amongst us, from failure to recognise that in the human race the mind tends to rule the body, and that sex in the human being is even more a mental passion than a physical instinct. This superficial view dims our perception of the causes which produce the facts around us; it also prevents our recognising the essential difference which exists between human and brute sex, and it blinds us to the imperative necessity of giving human education to this part of our nature.

As the study of the human body is carried on from its simpler to its more complex parts, it is perceived that the physiology of the more complex functions takes in a wider range of relations. The wise guidance of these more complex powers by parent or physician in health, and disease, demands a careful consideration of this extended range of relations. Thus the proper nourishment and exercise of the brain require more extended knowledge than the hygienic treatment of the skin, and diseases of the brain cause more serious danger to the individual. So all the faculties which belong to the life of relation—viz., the faculties which, like the senses, link us to our fellows—involve a broader range of study than those which appertain solely to those functions of the body which concern only the individual.

The portion of our organization most difficult of study, but also requiring the widest range of knowledge for its healthy guidance, is the faculty of sex. This faculty has a very complex aspect from its three-fold relation to the race, to men, and to women.

Sex is not essential to individual existence, but it is indispensable to the continuance of the race; and the progressive or retrograde character of the race largely depends upon the wisdom with which this faculty is guided in youth, and the character of the parental relations which are established.

A serious difficulty in understanding how to educate and regulate the relations of sex arises from the fact that it is the relation of two equal but distinct halves of the human race, and exists in the dual form—male and female. Unless the distinctive characteristics and requirements of each of these equal halves are fully understood, the relation between them cannot be satisfactory. The physiological meaning of the differences in organization between the sexes is at present very imperfectly understood.

The most striking distinction, however, in the manifestation of the sexual faculties exists between man and the brute creation, and is found in the mental or moral aspects which it assumes in man. The general structural resemblance between man and the lower animals affords no guidance to the education of this human faculty, for the differences between man and the lower animals are radically greater than the resemblance between them.

The most evident form of this mental difference shows itself as a sentiment of self-consciousness which is not observed in the brute. If an animal is not frightened by human beings it never hesitates in carrying on sexual congress in their presence, and neither before nor after the special act does it exhibit the smallest approach to shame in relation to it. In man, however, from the earliest dawn of the approaching faculty, self-consciousness is intense. This is not only observed in well brought-up boys and girls, who shrink from indecency of word or action, but it is never entirely extinguished in the most corrupt man or woman; and even the poor little waifs of our streets, blighted from earliest infancy, exhibit marked consciousness in their infantile depravity. All the vast difference between the gregariousness of the lower animals and the highest human civilization indicates the mental difference which moulds the human form of the sexual relations. Permanent parental care of offspring, mutual respect between the sexes, reverence for these faculties as typifying the mighty Creative Power of the universe, are stages of social progress based upon this mental difference in human and brute sex.

It is the mental or moral aspect of our sexual powers which, as society grows, shapes so much of the literature of every civilized country. In the popular ballads of a people, songs of love are even more abundant than patriotic songs; and as education spreads amongst the masses, romances and novels form the bulk of popular reading.