Some commenters are concerned that I’m setting up a straw man — that is, I’m leaving the doctrine of Original Sin undefined so that I can then dispute an unformed doctrine.  So I will defer to the BBC, and their excellent summary of the doctrine.  This will be our working definition of Original Sin:

What is original sin?
Original sin is a Christian doctrine that says that everyone is born sinful. This means that they are born with a built-in urge to do bad things and to disobey God.

Original sin is not just this inherited spiritual disease or defect in human nature; it’s also the ‘condemnation’ that goes with that fault.

An explanation for the evils of the world
Christians believe that original sin explains why there is so much wrong in a world created by a perfect God, and why people need to have their souls ‘saved’ by God.

A condition you’re in, not something you do
Original sin is a condition, not something that people do: It’s the normal spiritual and psychological condition of human beings, not their bad thoughts and actions. Even a newborn baby who hasn’t done anything at all is damaged by original sin.

The sin of Adam
In traditional Christian teaching, original sin is the result of Adam and Eve’s disobedience to God when they ate a forbidden fruit in the Garden of Eden.

Effects of original sin
Original sin affects individuals by separating them from God, and bringing dissatisfaction and guilt into their lives.

On a world scale, original sin explains such things as genocide, war, cruelty, exploitation and abuse, and the “presence and universality of sin in human history”.

Read the rest on the BBC.