Evangelium Vitae
60. Some people try to justify abortion by claiming that the result of conception, at least up to a certain number of days, cannot yet be considered a personal human life. But in fact, "from the time that the ovum is fertilized, a life is begun which is neither that of the father nor the mother; it is rather the life of a new human being with his own growth. It would never be made human if it were not human already. This has always been clear, and ... modern genetic science offers clear confirmation. It has demonstrated that from the first instant there is established the programme of what this living being will be: a person, this individual person with his characteristic aspects already well determined. Right from fertilization the adventure of a human life begins, and each of its capacities requires time—a rather lengthy time—to find its place and to be in a position to act".57 Even if the presence of a spiritual soul cannot be ascertained by empirical data, the results themselves of scientific research on the human embryo provide "a valuable indication for discerning by the use of reason a personal presence at the moment of the first appearance of a human life: how could a human individual not be a human person?". 58
Furthermore, what is at stake is so important that, from the standpoint of moral obligation, the mere probability that a human person is involved would suffice to justify an absolutely clear prohibition of any intervention aimed at killing a human embryo. Precisely for this reason, over and above all scientific debates and those philosophical affirmations to which the Magisterium has not expressly committed itself, the Church has always taught and continues to teach that the result of human procreation, from the first moment of its existence, must be guaranteed that unconditional respect which is morally due to the human being in his or her totality and unity as body and spirit: "The human being is to be respected and treated as a person from the moment of conception; and therefore from that same moment his rights as a person must be recognized, among which in the first place is the inviolable right of every innocent human being to life".59
61. The texts of Sacred Scripture never address the question of deliberate abortion and so do not directly and specifically condemn it. But they show such great respect for the human being in the mother's womb that they require as a logical consequence that God's commandment "You shall not kill" be extended to the unborn child as well.
Human life is sacred and inviolable at every moment of existence, including the initial phase which precedes birth. All human beings, from their mothers' womb, belong to God who searches them and knows them, who forms them and knits them together with his own hands, who gazes on them when they are tiny shapeless embryos and already sees in them the adults of tomorrow whose days are numbered and whose vocation is even now written in the "book of life" (cf. Ps 139: 1, 13-16). There too, when they are still in their mothers' womb—as many passages of the Bible bear witness60—they are the personal objects of God's loving and fatherly providence.
Christian Tradition—as the Declaration issued by the Congregation for the Doctrine of the Faith points out so well61—is clear and unanimous, from the beginning up to our own day, in describing abortion as a particularly grave moral disorder. From its first contacts with the Greco-Roman world, where abortion and infanticide were widely practised, the first Christian community, by its teaching and practice, radically opposed the customs rampant in that society, as is clearly shown by the Didache mentioned earlier. 62 Among the Greek ecclesiastical writers, Athenagoras records that Christians consider as murderesses women who have recourse to abortifacient medicines, because children, even if they are still in their mother's womb, "are already under the protection of Divine Providence".63 Among the Latin authors, Tertullian affirms: "It is anticipated murder to prevent someone from being born; it makes little difference whether one kills a soul already born or puts it to death at birth. He who will one day be a man is a man already".64
Throughout Christianity's two thousand year history, this same doctrine has been constantly taught by the Fathers of the Church and by her Pastors and Doctors. Even scientific and philosophical discussions about the precise moment of the infusion of the spiritual soul have never given rise to any hesitation about the moral condemnation of abortion.
62. The more recent Papal Magisterium has vigorously reaffirmed this common doctrine. Pius XI in particular, in his Encyclical Casti Connubii, rejected the specious justifications of abortion. 65 Pius XII excluded all direct abortion, i.e., every act tending directly to destroy human life in the womb "whether such destruction is intended as an end or only as a means to an end".66 John XXIII reaffirmed that human life is sacred because "from its very beginning it directly involves God's creative activity".67 The Second Vatican Council, as mentioned earlier, sternly condemned abortion: "From the moment of its conception life must be guarded with the greatest care, while abortion and infanticide are unspeakable crimes".68
The Church's canonical discipline, from the earliest centuries, has inflicted penal sanctions on those guilty of abortion. This practice, with more or less severe penalties, has been confirmed in various periods of history. The 1917 Code of Canon Law punished abortion with excommunication. 69 The revised canonical legislation continues this tradition when it decrees that "a person who actually procures an abortion incurs automatic (latae sententiae) excommunication".70 The excommunication affects all those who commit this crime with knowledge of the penalty attached, and thus includes those accomplices without whose help the crime would not have been committed. 71 By this reiterated sanction, the Church makes clear that abortion is a most serious and dangerous crime, thereby encouraging those who commit it to seek without delay the path of conversion. In the Church the purpose of the penalty of excommunication is to make an individual fully aware of the gravity of a certain sin and then to foster genuine conversion and repentance.
Given such unanimity in the doctrinal and disciplinary tradition of the Church, Paul VI was able to declare that this tradition is unchanged and unchangeable. 72 Therefore, by the authority which Christ conferred upon Peter and his Successors, in communion with the Bishops—who on various occasions have condemned abortion and who in the aforementioned consultation, albeit dispersed throughout the world, have shown unanimous agreement concerning this doctrine—I declare that direct abortion, that is, abortion willed as an end or as a means, always constitutes a grave moral disorder, since it is the deliberate killing of an innocent human being. This doctrine is based upon the natural law and upon the written Word of God, is transmitted by the Church's Tradition and taught by the ordinary and universal Magisterium. 73
No circumstance, no purpose, no law whatsoever can ever make licit an act which is intrinsically illicit, since it is contrary to the Law of God which is written in every human heart, knowable by reason itself, and proclaimed by the Church.
63. This evaluation of the morality of abortion is to be applied also to the recent forms of intervention on human embryos which, although carried out for purposes legitimate in themselves, inevitably involve the killing of those embryos. This is the case with experimentation on embryos, which is becoming increasingly widespread in the field of biomedical research and is legally permitted in some countries. Although "one must uphold as licit procedures carried out on the human embryo which respect the life and integrity of the embryo and do not involve disproportionate risks for it, but rather are directed to its healing, the improvement of its condition of health, or its individual survival",74 it must nonetheless be stated that the use of human embryos or fetuses as an object of experimentation constitutes a crime against their dignity as human beings who have a right to the same respect owed to a child once born, just as to every person. 75
This moral condemnation also regards procedures that exploit living human embryos and fetuses—sometimes specifically "produced" for this purpose by in vitro fertilization—either to be used as "biological material" or as providers of organs or tissue for transplants in the treatment of certain diseases. The killing of innocent human creatures, even if carried out to help others, constitutes an absolutely unacceptable act.
Special attention must be given to evaluating the morality of prenatal diagnostic techniques which enable the early detection of possible anomalies in the unborn child. In view of the complexity of these techniques, an accurate and systematic moral judgment is necessary. When they do not involve disproportionate risks for the child and the mother, and are meant to make possible early therapy or even to favour a serene and informed acceptance of the child not yet born, these techniques are morally licit. But since the possibilities of prenatal therapy are today still limited, it not infrequently happens that these techniques are used with a eugenic intention which accepts selective abortion in order to prevent the birth of children affected by various types of anomalies. Such an attitude is shameful and utterly reprehensible, since it presumes to measure the value of a human life only within the parameters of "normality" and physical well-being, thus opening the way to legitimizing infanticide and euthanasia as well.
And yet the courage and the serenity with which so many of our brothers and sisters suffering from serious disabilities lead their lives when they are shown acceptance and love bears eloquent witness to what gives authentic value to life, and makes it, even in difficult conditions, something precious for them and for others. The Church is close to those married couples who, with great anguish and suffering, willingly accept gravely handicapped children. She is also grateful to all those families which, through adoption, welcome children abandoned by their parents because of disabilities or illnesses.