In this way we shall, in time, be able to obtain a clear picture of the probable results on the offspring of unions between any kind of people. From personal and ancestral data we shall be able to reckon the probable quality of the offspring of a married couple. Given a man and woman of known personal qualities and of known ancestors, what are likely to be the personal qualities, physical, mental and moral, of the children? That is a question of immense importance both for the beings themselves whom we bring into the world, for the community generally, and for the future race. Eventually, it seems evident, a general system, whether private or public, whereby all personal facts, biological and mental, normal and morbid, are duly and systematically registered, must become inevitable if we are to have a real guide as to those persons who are most fit, or most unfit, to carry on the race.[151] Unless they are full and frank such records are useless. But it is obvious that for a long time to come such a system of registration must be private. According to the belief which is still deeply rooted in most of us, we regard as most private those facts of our lives which are most intimately connected with the life of the race, and most fateful for the future of humanity. The feeling is no doubt inevitable; it has a certain rightness and justification. As, however, our knowledge increases we shall learn that we are, on the one hand, a little more responsible for future generations than we are accustomed to think, and, on the other hand, a little less responsible for our own good or bad qualities. Our fiat makes the future man, but, in the same way, we are ourselves made by a choice and a will not our own. A man may indeed, within limits, mould himself, but the materials he can alone use were handed on to him by his parents, and whether he becomes a man of genius, a criminal, a drunkard, an epileptic, or an ordinarily healthy, well-conducted, and intelligent citizen, must depend at least as much on his parents as on his own effort or lack of effort, since even the aptitude for effective effort is largely inborn. As we learn to look on the facts from the only sound standpoint of heredity, our anger or contempt for a failing and erring individual has to give way to the kindly but firm control of a weakling. If the children's teeth have been set on edge it is because the parents have eaten sour grapes.