Here’s another place .
*“19. 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. 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.”
“The Supreme Pontiff Pope Paul VI, in an audience granted to the undersigned Secretary of the Sacred Congregation for the Doctrine of the Faith on June 28, 1974, has ratified this Declaration on Procured Abortion and has confirmed it and ordered it to be promulgated.”*
SACRED CONGREGATION FOR THE DOCTRINE OF THE FAITH
DECLARATION ON PROCURED ABORTION
June 28, 1974
vatican.va/roman_curia/congregations/cfaith/documents/rc_con_cfaith_doc_19741118_declaration-abortion_en.html