From a careful observation of youthful curiosity and a very vivid recollection of my own childhood, I have tried to explain frankly the points about which there is the greatest inquiry. These points are _not_ frankly or clearly explained in most sex literature. They are avoided, partly from embarrassment, but more, apparently, because those who have undertaken to instruct the children are not really clear in their own minds as to the proper status of the sex relation. I found that from the physiological point of view, the question was handled with limitations and reservations. From the point of natural science it was often handled with sentimentality, the child being led from a semi-esthetic study of the reproduction of flowers and animals to the acceptance of a similar idea for human beings. From the moral point of view it was handled least satisfactorily of all, the child being given a jumble of conflicting ideas, with no means of correlating them,--fear of venereal disease, one's duty to suppress “animal passion,” the sacredness of marriage, and so forth. And from the emotional point of view, the subject was not handled at all. This one omission seems to me to be the key to the whole situation, and it is the basis of the radical departure I have made from the precedents in most sex literature for children. Concerning all four points of view just mentioned, there are certain departures from the traditional method that have seemed to me worth making. On the physiological side I have given, as far as possible, the proper terminology for the sex organs and functions. Children have had to read the expurgated literature which has been specially prepared for them in poetic or colloquial terms, and then are needlessly mystified when they hear things called by their real names. On the side of natural science, I have emphasized our unlikeness to the plants and animals rather than our likeness, for while the points we have in common with the lower orders make an interesting section in our general education, it is knowing about the vital points in which we differ that helps us to solve the sexual problems of maturity; and the child needs that knowledge precisely as he needs knowledge of everything which will fortify him for wise decisions when he is grown. On the moral side, I have tried to avoid confusion and dogmatism in the following ways: by eliminating fear of venereal disease as an appeal for strictly limited sex relations, stating candidly that venereal disease _is_ becoming curable; by barring out all mention of “brute” or “animal” passion, terms frequently used in pleas for chastity and self control, as such talk is an aspersion on the brutes and has done children much harm in giving them the impression that there is an essential baseness in the sex relation; by inviting the inference that marriage is “sacred” by virtue of its being a reflection of human ideality rather than because it is a legalized institution.