— Pius XII.
, Context: Besides, every human being, even the child in the womb, has the right to life directly from God and not from his parents, not from any society or human authority. Therefore, there is no man, no human authority, no science, no "indication" at all—whether it be medical, eugenic, social, economic, or moral—that may offer or give a valid judicial title for a direct deliberate disposal of an innocent human life, that is, a disposal which aims at its destruction, whether as an end in itself or as a means to achieve the end, perhaps in no way at all illicit. Thus, for example, to save the life of the mother is a very noble act; but the direct killing of the child as a means to such an end is illicit. The direct destruction of so-called "useless lives," already born or still in the womb, practiced extensively a few years ago, can in no wise be justified. Therefore, when this practice was initiated, the Church expressly declared that it was against the natural law and the divine positive law, and consequently that it was unlawful to kill, even by order of the public authorities, those who were innocent, even if on account of some physical or mental defect, they were useless to the State and a burden upon it. The life of an innocent person is sacrosanct, and any direct attempt or aggression against it is a violation of one of the fundamental laws without which secure human society is impossible. We have no need to teach you in detail the meaning and the gravity, in your profession, of this fundamental law. But never forget this: there rises above every human law and above every "indication" the faultless law of God.
Allocution to Midwives on the Nature of Their Profession, October 29, 1951. http://www.ewtn.com/library/PAPALDOC/P511029.HTM http://www.papalencyclicals.net/Pius12/P12midwives.htm