You didn't answer my question. You just uttered a pronouncement. But I understand the problem; you can't answer my question. And that is because the newly born has committed no sin. In fact it will be a few years before the newly born will commit a sin.
If he wasn't a sinful being he wouldn't commit any sins when he was a few years old. Do you think sin only becomes sin when the person knows it is a sin? Animals don't commit sin because they are not sinful beings. Sin is against God. It only applies to his image bearers---moral creatures. All humans sin morally against God because they are bent that way, and they got bent that way because of their father Adam.
Here is something you have never addressed:
When Adam ate of the forbidden tree, and Eve too, they gained something that they didn't have before. The
knowledge of not only good, but also evil. Now they are changed, and all their posterity is changed in the very same way. All have the knowledge of both good and evil. Sometimes they do good, sometimes they do evil. And either choice is a self centered choice, not a choice based on a relationship with God or for his glory. When evil is judged and destroyed at Christ's return, there will be no more evil to know, only good. Only the Tree of Life, which is a type of Christ.
With that in mind, was Jesus dying on the cross undoing what Adam did for all people without exception at birth. Or was his dying in the place of those who he specifically died for----the ones given to him by the Father---- and for the purpose of undoing what Adam did for them by their being placed in him instead of in Adam, and also taking the just punishment for their personal sins? The first---of the earth, natural. The second of God, spiritual. 1 Cor 15. Planted one thing, (our body dies) raised another, same body but no longer in Adam. We are still in Adam naturally for the moment but we cannot be condemned by our sins or the Adamic nature. We are Christ's. Sealed in him by the Holy Spirit.