The sexual activity, in which husband and wife are intimately and chastely united with one another, through which human life is transmitted, is, as the recent Council recalled, "noble and worthy.'' It does not, moreover, cease to be legitimate even when, for reasons independent of their will, it is foreseen to be infertile. For its natural adaptation to the expression and strengthening of the union of husband and wife is not thereby suppressed.
The fact is, as experience shows, that new life is not the result of each and every act of sexual intercourse. God has wisely ordered laws of nature and the incidence of fertility in such a way that successive births are already naturally spaced through the inherent operation of these laws.
The Church, nevertheless, in urging men to the observance of the precepts of the natural law, which it interprets by its constant doctrine, teaches that each and every marital act must of necessity retain its intrinsic relationship to the procreation of human life.
This particular doctrine, often expounded by the magisterium of the Church, is based on the inseparable connection, established by God, which man on his own initiative may not break, between the unitive significance and the procreative significance which are both inherent to the marriage act.
The reason is that the fundamental nature of the marriage act, while uniting husband and wife in the closest intimacy, also renders them capable of generating new life—and this as a result of laws written into the actual nature of man and of woman. And if each of these essential qualities, the unitive and the procreative, is preserved, the use of marriage fully retains its sense of true mutual love and its ordination to the supreme responsibility of parenthood to which man is called. We believe that our contemporaries are particularly capable of seeing that this teaching is in harmony with human reason.
Pope Paul VI, Humanae Vitae, 11-12
Reflection – So here we have the paragraphs of the encyclical that resolve the question, from the point of view of a faithful Catholic wishing to move in obedience to Christ’s Church, of artificial contraception. The wording of the teaching is precise, careful, and needs to be quoted in its precision of expression. I have noticed that efforts to paraphrase this teaching or ‘simplify’ it always end up distorting it.
To repeat it, “each and every marital act must of necessity retain its intrinsic relationship to the procreation of human life. This particular doctrine, often expounded by the magisterium of the Church, is based on the inseparable connection, established by God, which man on his own initiative may not break, between the unitive significance and the procreative significance which are both inherent to the marriage act.”
So it is not “every sexual act must produce a baby,” (which is absurd) or “every time the couple has sex, they must be open to creating a baby” (which would be a ridiculous thing to ask of, say, an elderly married couple) or various other misleading simplifications. Those of us who do accept and want to promote this teaching have to be careful to do it justice. It is not a stupid or ridiculous doctrine, and so our presentation of it must not make it so.
We insist on this, on the necessity that every act of sexual union within a marriage (and that every act of sexual union be within a marriage) be both an expression of marital love and union (hence, as the next paragraph will state, marital rape is just as much a violation of the meaning of marriage as contraception), and be in its physical structure ordered towards the procreation of human life. This insistence flows from our whole Christian conviction of the sacredness of the body, the necessarily incarnate nature of our faith, that the meaning of things and the depths of what we believe about life must be expressed in the concrete actions of our bodily selves.
I cannot say, for example, that “Well, in general I try to be kind to people. The orientation of my life is towards kindness,” and then go around in specific instances treating people horribly, being rude and crass and insensitive. If I do this, I am a hypocrite, or at least a sinner (which I am, of course). The intentions of our hearts must be expressed in the actions of our bodies, and both the intentions of our hearts and the actions of our bodies must be in conformation with the designs of God.
But all of this, as I said yesterday, makes no sense outside of the larger context of discipleship, union with Christ, the universal call to holiness that is the real and lasting message of Vatican II. The Church is, in fact, paying lay people in the vocation of marriage the highest compliment of assuming that they are capable with God’s grace of heroic love and sacrifice, of being crucified with Christ so as to be victorious with and in him.
The living out of sexuality within marriage in accordance with the God-created structure of sexuality—that it is an act of physical union, meant to express the union of love of the couple, that is ordered to creating a new life—is a way, a means, an assured path, whereby the married couple in their mutual vocation are called into this heroic Christian love. And the re-shaping of sexual expression so that it no longer communicates union of love and openness to life in a single act is a frustration of that divine meaning of marriage, inscribed in the very bodies of man and woman, and that is the very definition of a moral evil.
And that is why the Church teaches that the use of artificial contraception is evil, and must be avoided.