What is the doctrine of original sin?

“Since, therefore, the curse, which goes about through all the regions of the world, flowed hither and yon from Adam’s guilty, it is not unreasonable if it is spread to all his offspring. Original sin, therefore, seems to be a hereditary depravity and corruption of our nature diffused into all parts of the soul.” - John Calvin, Institutes of the Christian Religion, Book 2, Chapter 1

“As the result of Adam’s transgression, men are born in sin and by nature are spiritually dead.” - Steele, Thomas, and Quinn, The Five Points of Calvinism, p. 20

Genesis 2:16-17; 3:6-7, 14-19, 22-24
We still feel the consequences of Adam’s sin today. But we do not read of the guilt of sin being passed on in Genesis.

Romans 5 is the key text

Romans 5:1, 12-21

The TEXT (Romans 5)

Augustine was the main early writer that talked about original sin. He was working from a Latin translation that had “in whom all sinned” in Romans 5:12. This is generally regarded as an inaccurate translation and possibly led to his misunderstanding of the verse.
Romans 5:13-14 - We all did not sin in the same way Adam did.
Romans 5:15-16 - If we believe we are all condemned by Adam’s sin, we must also believe all are automatically saved by Jesus’ sacrifice and no one goes to hell.
Romans 5:18-19 - Christ justifies all men when we do what He requires of us to take advantage of the blessing.
Romans 5:20-21 - Will we follow Adam’s path of sin or Jesus’ path of redemption?

The CONTEXT (Romans)

Romans 1:18
Romans 2:1, 23
Romans 4:5, 7
Romans 6:3-4, 11-12
Romans 11:22
Romans 6:23

OTHER TEXTS (the rest of the Bible)

Matthew 19:14 - Why would Jesus say this is children are born in sin?
Ezekiel 18:20 - The person who sins will die.
Romans 14:12