The application of these assumptions to the case of the predominant investigation-impulse seems to be subject to special difficulties, as one is unwilling to admit that this serious impulse exists in children or that children show any noteworthy sexual interest. However, these difficulties are easily obviated. The untiring pleasure in questioning as seen in little children demonstrates their curiosity, which is puzzling to the grown-up, as long as he does not understand that all these questions are only circumlocutions, and that they cannot come to an end because they replace only one question which the child does not put. When the child becomes older and gains more understanding this manifestation of curiosity suddenly disappears. But psychoanalytic investigation gives us a full explanation in that it teaches us that many, perhaps most children, at least the most gifted ones, go through a period beginning with the third year, which may be designated as the period of _infantile sexual investigation_. As far as we know, the curiosity is not awakened spontaneously in children of this age, but is aroused through the impression of an important experience, through the birth of a little brother or sister, or through fear of the same endangered by some outward experience, wherein the child sees a danger to his egotistic interests. The investigation directs itself to the question whence children come, as if the child were looking for means to guard against such undesired event. We were astonished to find that the child refuses to give credence to the information imparted to it, e.g., it energetically rejects the mythological and so ingenious stork-fable, we were astonished to find that its psychic independence dates from this act of disbelief, that it often feels itself at serious variance with the grown-ups, and never forgives them for having been deceived of the truth on this occasion. It investigates in its own way, it divines that the child is in the mother's womb, and guided by the feelings of its own sexuality, it formulates for itself theories about the origin of children from food, about being born through the bowels, about the rôle of the father which is difficult to fathom, and even at that time it has a vague conception of the sexual act which appears to the child as something hostile, as something violent. But as its own sexual constitution is not yet equal to the task of producing children, his investigation whence come children must also run aground and must be left in the lurch as unfinished. The impression of this failure at the first attempt of intellectual independence seems to be of a persevering and profoundly depressing nature.[23]