The doctrine of "original sin" and man's "depraved nature" was conceived initially, in it's earliest forms as being a "Christian doctrine", in the second century by Irenaeus, a bishop who cooked up much of the "catholic church's" doctrine, including "Maryology", which states that Mary was sinless (to uphold his false doctrine that man's nature is corrupt, and to try and explain why Jesus didn't have this conjectural fallen nature). The Jews reject this doctrine, and Christianity has it's roots Judaism. This teaching is clearly in error. A little on the history:
http://en.wikipedia.org/wiki/Original_sin#History_of_the_doctrine
That man's nature is corrupted was a foundational element in a very early form of Gnostic Christianity called Manichaeism, which Augustine formerly practiced before his supposed "conversion". Clearly Augustine never truly converted, and remained influenced by his former religion.
http://en.wikipedia.org/wiki/Manichaeism#Later_history
Thus we have it, all "Christian" theological systems that exist today were founded upon the same Gnostic premise that Adam's sin (in one form or another) is passed down through heredity and causes us (at some degree) to be sinful and unable to love God of our own volition, which was God's sole purpose in creating us to begin with, and this ability was never lost, although we do come into bondage to sin willfully and are thus corrupted by it. But God commands we repent, get ourselves new hearts and new minds, turn from our wickedness and begin to follow Him. And even though some forms of modern Christianity reject the doctrine of original sin, they still hold to other tenets that were necessitated by it, thus rendering their theology as false as well.
