"[W]hen the area of public controversy widens and the problems raised become more acute because of new chemical and biological discoveries, it will be useful to outline the history of the Christian Churches’ teachings on contraception. For centuries the Christian doctrine regarding deliberate family limitation was clear-cut and unambiguous. The primary (some Fathers of the Church claimed the ‘’only’’) aim of sexual intercourse in marriage was the procreation of children. Secondary aims such as mutual help between husband and wife or the alleviation of concupiscence were much less important in the marriage relationship. Any artificial interference with the natural processes of coitus and conception was contrary to the laws of god, and must be condemned as gravely sinful. St. Augustine of Hippo wrote: “Sexual intercourse even with a lawful wife is unlawful and shameful, if the offspring of children is prevented. This is what Onan, the son of Juda, did, and on that account God put him to death”. For priests of laymen to query these eternal and immutable laws as laid down by St. Augustine in the fourth, and elaborated by St. Thomas Aquinas in the thirteenth century, was not merely presumptuous but possibly heretical. Even the coming of the Reformation and all it represented in the way of challenge to the dogmas of the medieval Catholic Church had no apparent influence on Christian doctrine concerning birth control. Protestant divines were as much in agreement on this point as they were in disagreement about others."