Some believe that original sin was a doctrine concocted by Paul that has no roots in the Older Testament and Judaism. I’ve had people mention this a few times in discussions on original sin so I was delighted to see Michael Bird deal with this in his Introducing Paul.
It turns out that debates on original sin were not unique to Christianity. Many Jews disagreed on the relationship between Adam’s sin and its effect on the human race. Nevertheless, some had a position similar to what Paul espouses in Romans 5.
“O Adam, what have you done? For though it was you who sinned, the fall was not yours alone, but ours also who are your descendants.” (4 Ezra 7:118)