"There are two methods by which Catholics may know that a teaching of the Church is infallible and therefore must be obeyed by all Catholics in order to remain Catholic. The first of these, of course, is an ex cathedra pronouncement. Popes use this mechanism very infrequently, and then only to address the very fundamentals of Catholic faith. Only once since 1870 has the Pope spoken ex cathedra; on November 1, 1950, when Pope Pius XII declared the doctrine of the Assumption of the Blessed Virgin Mary. Many pro-life theologians have debated the wisdom of having the Church's teachings on birth control and abortion be formally declared infallible, and have decided that this would not be wise in the larger scheme of things. The reason is that such a pronouncement in an area of morals (as opposed to fundamental beliefs) would give the impression that all other moral teachings of the Church were optional. This might lead to a situation where disbelief would run rampant in the areas not specifically addressed ex cathedra, and would lead to more and more demands for such pronouncements in almost every area of Church teaching."