Dr Frank J. Ayd jr: 'Pius XII's statement on the pill' (allocution 12.9.1958, InternationalHematological Congress)Catholic Mind, January 1965, 49-54, here 52-4In 1953, Drs. Gregory Pincus and M. Chang at the Worcester Foundation for Experimental Biology reportedthat out of almost 200 drugs they tested, 3 were potent inhibitors of ovulation. One of these was Enovid. It wasselected for trials in humans, in preference to the others because it was the most active ovulation suppressant.Enovid was first used to treat inexplicably infertile women and later for contraceptive purposes beginning in1954 by Dr. John Rock and his associates. Their work substantiated the contraceptive efficacy of Enovid whichwas attributed to its inhibition of ovulation.In April, 1956, the first large scale field trial of Enovid was started in San Juan, Puerto Rico. A year later asecond project was begun in Humacao, Puerto Rico. In June, 1957, Enovid became commercially available.Thereafter, it was prescribed for contraception in many areas of the world. By 1958, its use had multiplied andspread. Articles on it were published in medical journals, it was discussed at medical meetings and it washeralded by Planned Parenthood and the lay press as the possible answer to the population problem.A man as well informed as Pius XII was, could not help but know about the existence and widespread use ofEnovid, especially in Catholic countries. Furthermore, because of moral questions raised by this drug, it islikely that Pius, as was his custom, sought the best medical opinions he could about Enovid, its uses and itsprobable modes of action.What prompted Pius to talk about Enovid at that particular time? He answered this by stating his concern aboutthe opinion of some theologians on the morality of oral contraception. Less than 4 months before he addressedthe hematologists, Louis Janssens wrote an article 'L'inhibition de l'ovulation est-elle moralement licite?',Ephemerides Theologicae Lovanienses 34 (1958) ...