If there were no likelihood of being taught badly about sex by other children, the matter could be left to the natural operation of the child’s curiosity, and parents could confine themselves to answering questions--always provided that everything became known before puberty. This, of course, is absolutely essential. It is a cruel thing to let a boy or girl be overtaken by the physical and emotional changes of that time without preparation, and possibly with the feeling of being attacked by some dreadful disease. Moreover, the whole subject of sex, after puberty, is so electric that a boy or girl cannot listen in a scientific spirit, which is perfectly possible at an earlier age. Therefore, quite apart from the possibility of nasty talk, a boy or girl should know the nature of the sexual act before attaining puberty. How long before this the information should be given depends upon circumstances. An inquisitive and intellectually active child must be told sooner than a sluggish child. There must at no time be unsatisfied curiosity. However young the child may be, he must be told if he asks. And his parents’ manner must be such that he will ask if he wants to know. But if he does not ask spontaneously, he must in any case be told before the age of ten, for fear of being first told by others in a bad way. It may therefore be desirable to stimulate his curiosity by instruction about generation in plants and animals. There must not be a solemn occasion, a clearing of the throat, and an exordium: “Now, my boy, I am going to tell you something that it is time for you to know.” The whole thing must be ordinary and every-day. That is why it comes best in answer to questions. I suppose it is unnecessary at this date to argue that boys and girls must be treated alike. When I was young, it was still quite common for a “well-brought-up” girl to marry before knowing anything about the nature of marriage, and to have to learn it from her husband; but I have not often heard of such a thing in recent years. I think most people recognize nowadays that a virtue dependent upon ignorance is worthless, and that girls have the same right to knowledge as boys. If there are any who still fail to recognize this, they are not likely to read the present work, so that it is not worth while to argue with them. I do not propose to discuss the teaching of sexual morality in the narrower sense. This is a matter as to which a variety of opinions exist. Christians differ from Mohammedans, Catholics from Protestants who tolerate divorce, freethinkers from mediævalists. Parents will all wish their children taught the particular brand of sexual morality in which they believe themselves, and I should not wish the State to interfere with them. But without going into vexed questions, there is a good deal that might be common ground.