There is no need for a revolutionary change of the marriage relations as proposed by the different brands of race-culture. The ultimate apotheosis of the world will never be reached by the superman on the terms of Nietzsche. The novel and revolutionary doctrine as to choice of parents has sprung in essentially unbalanced minds. If only those undesirables who become a public charge, either in prisons or in asylums—and sooner or later they all land there—are one way or another prevented from the propagation of their kind, the anti-selection, now at work, would cease. The degeneration of the human race could be stopped, even under the present conditions of human cultivation. CHAPTER XXI SEX-HYGIENE FOR ADULTS _Engagement._—The boy and girl who, by the proper and circumspect management of home and school, have succeeded to remain pure and chaste until their marriageable age need certain lessons in sexual hygiene to secure the desired happiness in their future married life. In the first place they ought to know that true marriage must be founded upon true love, not upon sensuality. Marriage founded upon blind passion, aroused by external qualities, is not capable of enhancing the spiritual and corporal resources of man and will never bring true happiness of any considerable duration. Real happiness does not lie in the realization of the desires. Only true love, not sensuality, can give life or enrich the life of the married couple. The essential for a happy union is that the contracting parties should be more or less each other’s equal. The “law of parity” is especially true in marriage. Like selects like. The young people should be of the same social position and, if possible, of equal education. Love is the union of sentiment, and lasting happiness in marriage is only possible where there is perfect understanding between husband and wife.