ROMANS 5:12: ORIGINAL SIN

The Catholic Douay Version of Romans 5:12 is based on a translation by St. Augustine. “Death passed from one man (Adam) to all men, in whom all sinned.” This is where the whole idea comes from that the original sin of Adam is automatically transmitted to each of us at birth. And from that concept comes logically two key Catholic doctrines: (1) the idea that infants who die without being baptized will go to limbo rather than heaven since even they possess sin at birth and (2) it explains the necessity of proposing the Immaculate Conception of Mary so that it could be said that she, and Jesus in turn, would be born entirely without sin. 

The problem is that Augustine mistranslated that verse, as most other versions of the Bible show: 

“death spread to all men because all men sinned.” (RSV)

"death spread to all because all have sinned" (NRSV)

 "death passed among all men for that all have sinned" (KJV)

"death pervaded the whole human race inasmuch as all have sinned" (NEB) 

 "death spread to all men because all sinned" (NASV)

"death has spread to the whole human race because everyone has sinned" (TEV)

"death came to all people because all sinned" (NIV)

"death has spread through the whole human race because everyone has sinned" (Jerusalem Bible)

Note especially that the last example comes from a Catholic Bible, although it points out in a footnote that the meaning is disputed and may instead refer to our sharing in Adam's sin instead.