I came across an article on an EO website whose author claims that the Catholic Church teaches “original guilt” rather than “original sin”. But this is not true. He also states that Catholics believe Mary was preserved free from contracting the stain of original sin by necessity; in other words, if Mary hadn’t received this singular privilege from God, Jesus would have been conceived and born in the state of original sin. However, the dogma states that Mary was conceived immaculately because it was fitting she be on account of her Divine Maternity. Not unlike the first Marian dogma, this third one is in principle Christo-centric. She had to be entirely holy and pure because her Son was from the moment he was conceived and incarnated (Luke 1:35). Jesus came into the world mentally and spiritually perfect. There was not the slightest flaw in his human constitution - no pride and not the least inclination to sin, just like Adam when he was originally created in God's image. For Jesus, it wasn't a matter of attaining perfection, but rather not falling from it. Jesus came into the world to restore it to God's grace and reverse the Fall. As the new Eve, Mary was intimately associated with her Son in his work of redemption. " "He became man by the Virgin, in order that the disobedience which proceeded from the serpent might receive its destruction in the same manner in which it derived its origin. For Eve, who was a virgin and undefiled, having conceived the word of the serpent, brought forth disobedience and death. But the Virgin Mary received faith and joy, when the angel Gabriel announced the good tidings to her that the Spirit of the Lord would come upon her, and the power of the Highest would overshadow her: wherefore also the Holy Thing begotten of her is the Son of God; and she replied, 'Be it unto me according to thy word.'" (St. Justin Martyr, Dialogue with Trypho, 100). "And thus also it was that the knot of Eve's disobedience was loosed by the obedience of Mary. For what the virgin Eve had bound fast through unbelief, this did the virgin Mary set free through faith" (St. Irenaeus, Against Heresies, 3:22). Not unlike her Divine offspring Jesus, Mary had to be entirely holy and sinless throughout her entire life in order to loose the knot of Eve's disobedience. The doctrine of the New Eve is totally senseless if Mary had been created short of perfection by being inclined to sin. Irenaeus equates Mary's spiritual purity and sinlessness with her virginity. She was as pure and spotless throughout her entire existence as Eve was before the Fall. And by being so, Mary restored in her person the state the woman had forfeited by her disobedience through her obedience. Concupiscence of the eyes and of the flesh transpired upon the Fall and were not causative of it. "The former [Eve] was seduced to disobey God, but the latter was persuaded to obey God, so that the Virgin Mary might become the advocate of the virgin Eve" (A.H. V.19.1).
‘If any one denies, that, by the grace of our Lord Jesus Christ, which is conferred in baptism, the reatum of original sin is remitted; or even asserts that the whole of that which has the true and proper nature of sin is not taken away; but says that it is only razed, or not imputed; let him be anathema.’
The General Council of Trent, Session V.
Anyway, some English translations of the original Latin text inaccurately read “the guilt of original sin is remitted.” Perhaps the author of that article was confused by a copy with this poor translation, though he doesn’t cite the Canon. Reatus refers to the state that accrues from a culpa (an actual wrong doing). Reatus culpa is guilt associated with the sentence (culpability). Reatus poena is the penalty of the sentence. Adam and Eve incurred the personal guilt (reatus culpa) of original sin and also the penalty (reatus poena). All their descendants at the moment they are conceived receive only the penalty of original sin (reatus poena). This penalty includes, for instance, being deprived of the original grace of justice and sanctity, the loss of integrity, ignorance, suffering, and death. All of us have been banned from paradise and are capable of committing sins once we have reached the age of reason. There is no human being who has never sinned besides Mary. Babies are born deprived of sanctifying grace; they suffer and die, even soon after they are born, since they all do in fact grow without exception only to commit personal sins of their own. So although babies and very young children aren’t personally guilty of having committed any sins (reatus culpa), they still incur the penalty of original sin (reatus poena), because they are capable of sinning once they are old enough. Many of them do in fact suffer and die while still too young. No descendant of Adam and Eve is culpable of eating the forbidden fruit in the Garden of Eden, but they still receive the penalty of original sin. A just God would not exact this penalty unless all human beings were guilty in some sense. Culpa contracta is the special phrase the Catholic Church uses to distinguish personal guilt (reatus culpa) from contracted guilt by association, which equals reatus poena. Hence, the Catholic Church does not teach original guilt. The personal sin of Adam is not imputed to us. If it were, God would certainly be unjust. But as Adam's descendants, we do receive the same penalty for his wrongdoing, since we all do sin once we are mature enough.