The Pontifical Commission on Birth Control was a committee within the Roman Curia tasked with analyzing the modern impact of birth control on the Roman Catholic Church. The disagreements within the commission ultimately led to the publication of the encylical Humanae Vitae.
With the appearance of the first oral contraceptives in 1960, dissenters in the Church argued for a reconsideration of the Church positions. In 1963 Pope John XXIII established a commission of six European non-theologians to study questions of birth control and population. Neither John XXIII nor Paul VI wanted the almost three thousand bishops and other clerics then in Rome for Vatican II to address the birth control issue even though many of these bishops expressed their desire to bring this pressing pastoral issue before the Council.
After John's death in 1963, Pope Paul VI added theologians to the commission and over three years expanded it to 72 members from five continents (including 16 theologians, 13 physicians and five women without medical credentials, with an executive committee of 16 bishops, including seven cardinals without medical credentials.)
The commission produced a report in 1966, proposing that artificial birth control was not intrinsically evil and that Catholic couples should be allowed to decide for themselves about the methods to be employed. According to the majority report, use of contraceptives should be regarded as an extension of the already accepted cycle method:
The acceptance of a lawful application of the calculated sterile periods of the woman--that the application is legitimate presupposes right motives--makes a separation between the sexual act which is explicitly intended and its reproductive effect which is intentionally excluded. The tradition has always rejected seeking this separation with a contraceptive intention for motives spoiled by egoism and hedonism, and such seeking can never be admitted. The true opposition is not to be sought between some material conformity to the physiological processes of nature and some artificial intervention. For it is natural to man to use his skill in order to put under human control what is given by physical nature. The opposition is really to be sought between one way of acting which is contraceptive and opposed to a prudent and generous fruitfulness, and another way which is, in an ordered relationship to responsible fruitfulness and which has a concern for education and all the essential, human and Christian values.