I am, moreover, sceptical _because the very persons to whom to-day we have to look to effect the sexual enlightenment of children, are themselves to a great extent also in need of enlightenment_; and in respect of many of the questions about which the child has to be enlightened, no general harmony of scientific opinion can as yet be said to obtain. Take, for example, the question whether masturbation during the period of sexual development is or is not a physiological act; or the question whether sexual abstinence can do any harm to the health. It is true that such differences in scientific opinion are not so extensive as gravely to affect the question of the sexual enlightenment of the child. In the matter of sexual abstinence, for example, the majority of physicians are to-day agreed upon the view that such abstinence in general does no harm; and that those, if any, whose health may be unfavourably influenced by sexual abstinence, constitute at most a very small minority. In my own view, the persons who may suffer from this cause are those affected with hyperaesthesia of the sexual impulse, and in whom the impulse is dominant to such a degree that it interferes with all their alternative activities. But it is certainly only an extremely small percentage of persons about whom, among medical men able to speak authoritatively, that there is any difference of opinion. A more serious matter is the extent to which erroneous views about sexual questions still prevail among the populace. A father who starts with the false assumption that his son must inevitably have intercourse with so many prostitutes and must seduce so many girls--in a word, a father who regards sexual abstinence as unmanly, or as necessarily dangerous to health (and fathers who hold such opinions are no rarity)--such a father must himself be sexually enlightened before we give him the right to enlighten his son. Those also themselves greatly need enlightenment who, for instance, advise a young bridegroom who has always lived a chaste life to visit a prostitute before marriage, in order to prove his sexual potency. As if potency in intercourse with an experienced prostitute, skilled in all the tricks of her trade, were a proof that the bridegroom will prove sexually potent in intercourse with a chaste woman; or as if, on the other hand, the fact that a man proves impotent when he attempts intercourse with a prostitute whose embraces are repulsive to him, were in any sense whatever a proof that the same man will fail to effect intercourse with the woman he loves. Thus, many full-grown men are in need of enlightenment about this matter of sexual potency, and especially need information regarding the extent of the individual variations in this matter. We hear of young men who believe themselves to be ill, simply because they are not sexually potent to a degree that enables them to effect complete sexual intercourse several times in brief succession.