How should I respond to the claim that the church allowed abortion up to 166 days’ gestation until Pope Pius IX in 1869 declared all abortions wrong?
The short answer to your question is that the church has never allowed abortion, at any stage of development of the foetus. The condemnation of abortion is one of the church’s oldest and most consistent moral teachings, dating back to the first century.
One of the earliest condemnations comes in the Didache, written around AD 70–100. It states clearly: “You shall not murder a child by abortion nor kill what is begotten.”
Likewise, the Epistle of Barnabas, written in the late first or early second century, says: “You shall not slay the child by procuring abortion; nor, again, shall you destroy it after it is born” (Chap. 19).
The church Fathers, too, consistently defended unborn life. Writers such as Tertullian, Athenagoras of Athens, St Basil the Great and St John Chrysostom condemned abortion as a grave sin. Tertullian argued that “to prevent birth is anticipated murder”, emphasising that the child in the womb is already a human being.
Athenagoras defended Christians before the Roman authorities by pointing out that they regarded women who procured abortions as murderers. During the Middle Ages, theologians continued to condemn abortion, even though they debated the philosophical question of when the soul entered the body.
Following the philosophy of Aristotle, who taught that the human soul entered the body 40 days after conception for males and 90 days for females, some theologians, including St Thomas Aquinas, accepted the idea of “delayed ensoulment” – that the soul entered the body sometime after conception.
Nevertheless, Aquinas still considered abortion a grave moral evil because it deliberately frustrated the natural development of human life and violated God’s creative purpose. As you note, in 1869 Pope Pius IX removed the distinction between “formed” and “unformed”, or “animated” and “unanimated”, foetuses.
By the papal bull Apostolicae Sedis Moderationi, he declared that anyone who procured an abortion at any stage of pregnancy would automatically incur the penalty of excommunication. This reflected a growing recognition that distinctions based on when the soul entered the body were both uncertain and unnecessary.
The church’s condemnation of abortion continued in the twentieth century in documents such as Pope Pius XI’s encyclical Casti Connubii (1930), the Second Vatican Council’s Gaudium et Spes (1965), St Paul VI’s Humanae Vitae (1968) and St John Paul II’s Evangelium Vitae (1995).
In 1974, the Congregation for the Doctrine of the Faith dealt explicitly with the question of ensoulment in its Declaration on Procured Abortion. It stated:
“This declaration expressly leaves aside the question of the moment when the spiritual soul is infused…”
The declaration concluded that the church’s moral teaching does not depend on resolving the philosophical question of ensoulment. Even if one were to suppose a delayed ensoulment, abortion still destroys a developing human life ordered towards receiving a soul.
Moreover, because it can never be proven that the soul is absent at any stage, abortion always involves the unacceptable risk of killing an innocent human person. Independently of when the soul enters the body, the church has consistently taught that abortion is a serious moral evil.
At the same time, the church, as a most merciful mother, always welcomes back into her bosom those who have participated in abortion and who come to her repentant and seeking forgiveness.
