Excerpts from Humanae Vitae

These sections from Pope Paul VI's encyclical, On Human Life, are relevant to the discussion of in vitro fertilization. In fact, these teachings provide the foundation for the pro-life position against IVF.

Section 10:

Hence conjugal love requires in husband and wife an awareness of their mission of "responsible parenthood," which today is rightly much insisted upon, and which also must be exactly understood. Consequently it is to be considered under different aspects which are legitimate and connected with one another.

In relation to the biological processes, responsible parenthood means the knowledge and respect of their functions; human intellect discovers in the power of giving life biological laws which are part of the human person.

In relation to the tendencies of instinct or passion, responsible parenthood means that necessary dominion which reason and will must exercise over them.

In relation to physical, economic, psychological and social conditions, responsible parenthood is exercised, either by the deliberate and generous decision to raise a numerous family, or by the decision, made for grave motives and with due respect for the moral law, to avoid for the time being, or even for an indeterminate period, a new birth.

Responsible parenthood also and above all implies a more profound relationship to the objective moral order established by God, of which a right conscience is the faithful interpreter. The responsible exercise of parenthood implies, therefore, that husband and wife recognize fully their own duties towards God, towards themselves, towards the family and towards society, in a correct hierarchy of values.

In the task of transmitting life, therefore, they are not free to proceed completely at will, as if they could determine in a wholly autonomous way the honest path to follow; but they must conform their activity to the creative intention of God, expressed in the very nature of marriage and of its acts, and manifested by the constant teaching of the Church.

Section 14:

In conformity with these landmarks in the human and Christian vision of marriage, we must once again declare that the direct interruption of the generative process already begun, and, above all, directly willed and procured abortion, even if for therapeutic reasons, are to be absolutely excluded as licit means of regulating birth.

Equally to be excluded, as the teaching authority of the Church has frequently declared, is direct sterilization, whether perpetual or temporary, whether of the man or of the woman. Similarly excluded is every action which, either in anticipation of the conjugal act, or in its accomplishment, or in the development of its natural consequences, proposes, whether as an end or as a means, to render procreation impossible.

To justify conjugal acts made intentionally infecund, one cannot invoke as valid reasons the lesser evil, or the fact that such acts would constitute a whole together with the fecund acts already performed or to follow later, and hence would share in one and the same moral goodness. In truth, if it is sometimes licit to tolerate a lesser evil in order to avoid a greater evil or to promote a greater good, it is not licit, even for the gravest reasons, to do evil so that good may follow therefrom; that is, to make into the object of a positive act of the will something which is intrinsically disorder, and hence unworthy of the human person, even when the intention is to safeguard or promote individual, family or social well-being. Consequently it is an error to think that a conjugal act which is deliberately made infecund and so is intrinsically dishonest could be made honest and right by the ensemble of a fecund conjugal life.

Section 25:

And now our words more directly address our own children, particularly those whom God calls to serve Him in marriage. The Church, while teaching imprescriptible demands of the divine law, announces the tidings of salvation, and by means of the sacraments opens up the paths of grace, which makes man a new creature, capable of corresponding with love and true freedom to the design of his Creator and Savior, and of finding the yoke of Christ to be sweet.

Christian married couples, then, docile to her voice, must remember that their Christian vocation, which began at baptism, is further specified and reinforced by the sacrament of matrimony. By it husband and wife are strengthened and as it were consecrated for the faithful accomplishment of their proper duties, for the carrying out of their proper vocation even to perfection, and the Christian witness which is proper to them before the whole world. To them the Lord entrusts the task of making visible to men the holiness and sweetness of the law which unites the mutual love of husband and wife with their cooperation with the love of God the author of human life.

We do not at all intend to hide the sometimes serious difficulties inherent in the life of Christian married persons; for them as for everyone else, "the gate is narrow and the way is hard, that leads to life." But the hope of that life must illuminate their way, as with courage they strive to live with wisdom, justice and piety in this present time, knowing that the figure of this world passes away.

Let married couples, then, face up to the efforts needed, supported by the faith and hope which "do not disappoint … because God's love has been poured into our hearts through the Holy Spirit, who has been given to Us"; let them implore divine assistance by persevering prayer; above all, let them draw from the source of grace and charity in the Eucharist. And if sin should still keep its hold over them, let them not be discouraged, but rather have recourse with humble perseverance to the mercy of God, which is poured forth in the sacrament of Penance. In this way they will be enabled to achieve the fullness of conjugal life described by the Apostle: "husbands, love your wives, as Christ loved the Church … husbands should love their wives as their own bodies. He who loves his wife loves himself. For no man ever hates his own flesh, but nourishes and cherishes it, as Christ does the Church … this is a great mystery, and I mean in reference to Christ and the Church. However, let each one of you love his wife as himself, and let the wife see that she respects her husband."

Also see:

• Artificial fertilization and the Christian response