"With the arrival of the birth control pill in 1960, many believed the Church was about to change the position it had held for centuries. The Church was in the midst of reform, and in this climate of modernization it seemed possible that the Vatican might bend on birth control. Since 1957, Church law had allowed women with "irregular" cycles to take the Pill to regularize their cycle and enable them to better practice the rhythm method. Approval of the contraceptive pill, many believed, was soon to follow. Pro-Pill Catholics had a powerful ally on their side. John Rock, the eminent Catholic physician who had carried out Pill trials with Dr. Gregory Pincus, publicly argued that the Pill was merely an extension of the body's normal functioning. Since the Pill used the same hormones already present in the female reproductive system and did not tamper with sperm, Rock believed the Church should view the Pill as a "natural" form of contraception. The Vatican convened a commission to study the question of the Pill, but the Church would take eight years to determine its policy towards the Pill. In the interim, the Pill quickly became the most popular method of birth control among American women —regardless of religion."