Technically, swinging an unbreathing baby’s body against a tree, vice one that is breathing, makes an enormous difference. One is not considered physically alive upon examination, while the other is considered a living human.
In the classic creationist vs seminal argument, either God creates the individual soul or the genetics are passed from generation to generation and the separate soul is created by its parents.
If it created by its parents and not by God, then it is accountable to its parents for its final destiny and not to God.
Which is it, is the soul created by Man or by God?
The more sound Catholic position would be the Creationist position, but when it became politically popular to adapt the seminal position to attempt to discourage abortion, the Catholic Church pronounced life began in the womb. There are links back to Augustine and Origen, but basically the issue boils down to ‘who started soul life’?
BTW, the issue isn’t as simple as stating, “science declares the beginning of human life to begin when...”. Science fails to recognize a trichotomous anthropology of man. Not only failing to discern between body and soul, but also failing to even identify the human spirit, which is included in the Christian concept of human life and the identification of a person. This is no small issue, because the lack of human spirit made holy by God makes all the difference between rotting in the lake of fire for all future eternity and being sanctified and residing with God in heaven for all future eternity.
So, if the baby has an obstruction in his throat you can kill him?
The argument that life begins with breath hence abortion is acceptable is one of convenience not one of rigor or reverence.