First, let me re-post the text of Article IX:
Of Original or Birth Sin
Original sin standeth not in the following of Adam (as the Pelagians do vainly talk), but it is the fault and corruption of the nature of every man that naturally is engendered of the offspring of Adam, whereby man is very far gone from original righteousness, and is of his own nature inclined to evil, so that the flesh lusteth always contrary to the spirit; and therefore in every person born into this world, it deserveth God's wrath and damnation. And this infection of nature doth remain, yea, in them that are regenerated, whereby the lust of the flesh, called in Greek phronema sarkos (which some do expound the wisdom, some sensuality, some the affection, some the desire of the flesh), is not subject to the law of God. And although there is no condemnation for them that believe and are baptized, yet the Apostle doth confess that concupiscence and lust hath itself the nature of sin.
De Peccato Originali
Peccatum originis non est (ut fabulantur Pelagiani) in imitatione Adami situm, sed est vitium et depravatio naturae eiuslibet hominis ex Adamo naturaliter propagati, qua fit ut ab originali iustitia quam longissime distet, ad malum sua natura propendeat, et caro semper adversus spiritum concupiscat; unde in unoquoque nascentium iram Dei atque damnationem meretur. Manet etiam in renatis haec naturae depravatio, qua fit ut affectus carnis, Graece phronema sarcos (quod alii sapientiam, alii sensum, alii affectum, alii studium carnis interpretantur), legi Dei non subiiciatur. Et quanquam renatis et credentibus, nulla propter Christum est condemnatio, peccati tamen in sese rationem habere concupiscentiam fatetur Apostolus.
From this article, we can see why people object to what Original Sin states. Imagine holding your new first-born child in your arms, the first time you gaze upon a new life, frail, tender, a little bundle of reflexes and then thinking that this new baby "deserveth God's wrath and damnation" by virtue of its original sin. Can we honestly hold it to be true that the natural destiny of humanity is the fiery furnace of Hell?
We do need to be careful on many fronts here. First of all, this is an emotive issue and we can allow our emotions to wander in areas where a clearer head is needed. We must also be clear that there is a place for our emotion and that our sense of outrage at such a statement has a justifiable cause and needs an appropriate outlet.
Let us first be very careful and establish precisely what, according to the article, "deserveth God's wrath and damnation". If we just check the Latin carefully (thought the Cranmerian English is just as ample) "unde in unoquoque nascentium iram Dei atque damnationem meretur" we ask ourselves, what is the object of the passive meretur? Whatever it is, it is in every human being born. It seems to me to be quite clear that it is the Original Sin itself which is deserving the condemnation of God and from this we can infer that it is the cause of this Original Sin who will bear the brunt of God's wrath.
Nonetheless, the Doctrine of Original Sin is scriptural - St Paul's letter to the Romans (v.19) for instance. "As in Adam, all die..." or 1 Cor xv.21. These make it clear to me that the natural end of humanity is not Hell, we are meant (predestined, if you will) for Heaven and for Eternal Life - that is what God wants for us. Hell is the unnatural destiny of Man.
So what happens when we look at our little infant snuggled, sleeping soundly in our arms? Can we call that baby a sinner, by virtue of that original sin? To do so, again, misses a point - can we call anyone a sinner by virtue of original sin? I've mentioned this before - the Church only has the keys to heaven. According to the Apocalypse, it is some great archangel who possesses the key to Hell and he works only at the direct command of God, not of the Church. While we are in this life, we do not possess the wherewithal to judge sinners (motes and beams and what have you). In fact it is a consequence of Original Sin that we do not possess the wherewithal to judge sinners. Our own personal choice within us to Heaven or to Hell lies between ourselves and God.
Well, then? Is it possible for a tiny infant to be a sinner, to be stained with Original Sin? Clearly, the baby is innocent of actual sin i.e. sins which are committed by conscious act. However, as a consequence of a Pro-Life stance, the Catholic Faith teaches that human life begins at conception. If that child is fully human from that point, then it is capable of free choice at that point (a defining aspect of humanity). If so, then it is free to choose between right and wrong and is thus capable of sin even from the word "go".
However, capable does not mean that sin has taken place. We need then to look at Original Sin and how it is transmitted. How can the sin of one man infect all of his descendents? Well, the Story of the Fall makes it clear, the presence of the Serpent from the outset infects humanity by temptation, by lies and by the leading away from God. Even if an infant does not actually sin, it is still subject to being drawn into the darkness. Even Hitler was a newborn baby once.
This, then, reveals the need for the Baptism for infants. The Baptism rite contains an exorcism which is there to free the child from the clutches of the Devil. Of course, the child may still sin after Baptism, but that Baptism puts the child back into the track of its natural destiny, i.e. to God and to Heaven. Faith may be shipwrecked and the child may still fall away from God, but, with that Baptism into the Death of Christ there will always be that chance to take advantage of the Grace given to us in that Baptism to pull us back into the Light.
For children who die before Baptism, I cannot possibly comment on their destiny. I do not believe in a blanket condemnation to Limbo, and neither does the RCC now. The decision lies between God and the individual soul.
I did say that this is an emotional issue, and it is. Sin is a serious, serious, problem and one that does indeed affect (and infect) every child that comes into the world, transmitted by those already present. The least we can do is to ensure that all children get led into the Light and have the opportunity to be drawn by God. This cannot be any more important than for the unborn and is another reason why we need to stop abortion for the good of these little souls.