RESUMO
The understanding of the full truth and beauty of the marital relationship has developed from a remedy for concupiscence (cf. 1 Cor 7:9) to "a sacrament of mutual sanctification and an act of worship" (St. John Paul II). With this development came a realization of the need to respond to the dilemma of couples who legitimately and responsibly wanted to avoid pregnancy but in fidelity to the Church's consistent teaching against contraception. In the middle of the last century, Dr. John Billings undertook to assist in the quest to find a reliable means of preventing pregnancy, which was in accord with natural moral law. He was aided in this quest by his wife Dr. Evelyn Billings and the many couples who contributed to the research. Their discovery formed the basis of all modern methods of natural family planning. "[T]he difference, both anthropological and moral, between contraception and recourse to the rhythm of the cycle is a difference which is much wider and deeper than is usually thought. The choice of the natural rhythms involves accepting the cycle and thereby accepting dialogue, reciprocal respect, shared responsibility and self-control. In this context the couple comes to experience how conjugal communion is enriched with those values of tenderness and affection which constitute the inner soul of human sexuality, in its physical dimension also". Nontechnical Summary: Pope Saint Paul VI's magnificent but much misunderstood encyclical "Humanae Vitae" called on men of science "to labour to explain more thoroughly the various conditions favouring a proper regulation of births." To doctors he asked that they "persevere in promoting on every occasion the discovery of solutions inspired by faith and right reason". Dr John Billings and his wife, Dr Evelyn Billings, devoted their lives to answering these calls which the Holy Father also made to them in person some years after he gave his encyclical to the Church.