65 All of which agrees with the stern words of the Bishop of Hippo in denouncing those wicked parents who seek to remain childless, and failing in this, are not ashamed to put their offspring to death: "Sometimes this lustful cruelty or cruel lust goes so far as to seek to procure a baneful sterility, and if this fails the fetus conceived in the womb is in one way or another smothered or evacuated, in the desire to destroy the offspring before it has life, or if it already lives in the womb, to kill it before it is born. If both man and woman are party to such practices they are not spouses at all; and if from the first they have carried on thus they have come together not for honest wedlock, but for impure gratification; if both are not party to these deeds, I make bold to say that either the one makes herself a mistress of the husband, or the other simply the paramour of his wife."
Source: Casti Connubii (Vatican.va)