“Ask a Priest: When does a person acquire a soul?”

Q: If I may, a two-part question: 1. When does the human person acquire a soul? Is it infused by God at the moment of the person’s conception? 2. In the sad case of a test-tube baby or in vitro fertilization, when or how does that embryo/fetus/person acquire a soul? -J.S.

Answered by Fr. Edward McIlmail, LC

A: Actually the Church has never definitively said when the ensoulment of the human embryo occurs. It remains an open question. The Church does insist, however, that the human embryo must be treated as if it has the same dignity as you and I from the first moment of existence (see Holy See’s 2008 instruction Dignitas Personae, No. 5).

The embryo should be treated as if it were a person from the moment of conception, even if it is theoretically possible that it might not yet be so. The Church takes this nuanced position, in part, because there is no unanimous philosophical tradition on this point. It also notes that the exact timing of ensoulment in the human embryo is irrelevant to the question of whether an embryo could be destroyed, say, for research purposes. The benefit of the doubt dictates that the embryo should be respected as if it is already a person (though a tiny one, at that).

In 1974 the Congregation for the Doctrine of the Faith published its “Declaration on Procured Abortion.” Your particular questions point us to a key text in endnote No. 19, which says:

“This declaration expressly leaves aside the question of the moment when the spiritual soul is infused. There is not a unanimous tradition on this point and authors are as yet in disagreement. For some it dates from the first instant; for others it could not at least precede nidation [implantation in the uterus]. It is not within the competence of science to decide between these views, because the existence of an immortal soul is not a question in its field. It is a philosophical problem from which our moral affirmation remains independent for two reasons: (1) supposing a belated animation, there is still nothing less than a human life, preparing for and calling for a soul in which the nature received from parents is completed, (2) on the other hand, it suffices that this presence of the soul be probable (and one can never prove the contrary) in order that the taking of life involve accepting the risk of killing a man, not only waiting for, but already in possession of his soul.”

Complicating the debate are new embryological details such as twinning. This is when an embryo at an early stage splits into two. Does that mean the first embryo was the “parent” of the second? Or that the first embryo, until that point, was just a mass of cells? Suffice it to say that we need to respect the dignity of any embryo, before or after any potential splitting. (For further reading, click here.)

In the case of embryos created by in vitro fertilization, the question becomes even more complex. The instruction Dignitas Personae in No. 19 says, “All things considered, it needs to be recognized that the thousands of abandoned embryos represent a situation of injustice which in fact cannot be resolved.” (For more reading, check out the National Catholic Bioethics Center.)

Problems over the widespread abuse of embryos, along with the permissive attitudes toward abortion, drive home ever more clearly the need for a culture of life. To that end we work as best we can, and pray for the day when the world sees the light.

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