Calvinist, R.C. Sproul: “Original sin is the corruption visited on the progency of our first parents as punishment for the original transgression. Virtually every Christian church has some doctrine of original sin.” (What is Reformed Theology?, p.121, emphasis mine)
The Pelagians had rejected the doctrine of Original Sin, while the Semi-Pelagians had taken the opposite position. Arminianism also affirms Original Sin, though understood differently from Calvinism.
One member of The Society of Evangelical Arminians: “No one is condemned with Adam without becoming a partaker in his deeds. We fall short of the glory of God by sinning, not merely being conceived with a sinful nature.”
This speaks to the issue of Imputed Sin. If true, then it means that babies who die in infancy are not sent to Hell. The alternative, which Augustine taught, and which those who stress the importance of infant baptism, is that those babies who die in infancy are indeed imputed with sin, and thus perish in Hell for eternity.
One member of The Society of Evangelical Arminians: “Ask him if aborted Babies go to Hell. Are they conceived - then wake up in Hell? If he says yes, then ask him if he realizes that biologically over half of all conceptions end in a natural abortion, so therefore, over half of Hell would be populated by people who never willfully sinned; people who had no concept of life.”
Now it should also be pointed out, that some Calvinists do believe that even though a baby or infant may demonstrate the traits of the fallen nature, they are not yet culpable for guilt, since they are not in a “condition of accountability,” and therefore on that account, are not condemned with Adam.
But instead of presuming upon Calvinistic Unconditional Election, one alternative is that whereas deceased babies may demonstrate the traits of the fallen nature, they do not yet have sin imputed to them by God, and hence are not barred from Heaven upon death. Romans 5:12-14 states: “Therefore, just as through one man sin entered into the world, and death through sin, and so death spread to all men, because all sinned--for until the Law sin was in the world, but sin is not imputed when there is no law. Nevertheless death reigned from Adam until Moses, even over those who had not sinned in the likeness of the offense of Adam, who is a type of Him who was to come.” The idea is that there is no Law for babies, or those who have not yet reached the age or condition of accountability, and so although they may display the traits of the fallen Adamic nature, then is no imputation of sin, where there is no applicable Law.