Since the natural law evidently prescribes that man must live in society and that the human race which constitutes this society, is to be preserved by the generation of new human beings who will replace those that die, or are made useless by disease or other accident, whatever tends to this sustention of humanity according to the natural law, and in the proper conditions, is good, and whatever tends to the destruction of humanity is evil and to be avoided. The generation of new replacing human beings must take place only in the state of marriage, because thus solely the wife and the child are protected, the children are educated physically, mentally and morally, and the degradation and bestiality of promiscuous sexual relationship are averted. The first and principal end of marriage is the procreation of children. That end of marriage must be the end on which is founded primarily the natural necessity for this contract, but the natural necessity for the contract is the propagation of the human kind through lawful generation and education. Marriage, too, in its very nature is fitted for that chief end, and for that end it was instituted by the Author of nature--a stable, perpetual association of the sexes for the attainment of what is requisite for the propagation of mankind. There are secondary ends of marriage, such as a reciprocal love and help of the husband and wife, and also that aspect of marriage which makes it a restraint upon promiscuous lust. These last, however, are not enough to justify marriage in themselves without the first or chief end, which is the procreation of children. Whatever is subversive of the end of marriage, and that is the propagation of mankind, is subversive of the very foundation of human society, is contrary to the nature of man, frustrates the primal function of nature, and is therefore essentially and always evil, as bestiality, sodomy, or incest are evil. Such is birth control as ordinarily practised. Birth control if it is effective through a reciprocal consent of a wedded couple, for grave reason, and solely by mutual abstention from the _debitum_ may be in certain conditions an indifferent act morally. If, however, birth control is effected by contraceptive drugs, or like methods, it is a crime against nature, and always a crime which no circumstance can excuse, no more than no circumstance can excuse bestiality, sodomy, or incest. Secondly, marriage, which was instituted primarily to perpetuate the creative act of God, when such practices prevail degenerates to mere concubinage, a gratification of lust protected from the police. Such practices, moreover, lower man and woman below the brutes, because brutes do not frustrate the natural law except in the case of the male rat and a few other low grade rodents and boar pigs. Onan is the patron of Birth Control advocates. The Book of Genesis said Onan, the son of Judah, "did a detestable thing, therefore the Lord slew him."