18. We know what seriousness the problem of birth control can assume for some families and for some countries. That is why the last Council and subsequently the encyclical "Humanae vitae" of July 25, 1968, spoke of "responsible parenthood."[²⁴] What we wish to say again with emphasis, as was pointed out in the conciliar constitution "Gaudium et spes," in the encyclical "Populorum progressio" and in other papal documents, is that never, under any pretext, may abortion be resorted to, either by a family or by the political authority, as a legitimate means of regulating births.[²⁵] The damage to moral values is always a greater evil for the common good than any disadvantage in the economic or demographic order.