One of St. Augustine's concerns (later mentioned by Bertrand Russell) is that
- if it is the soul that sins, and
- the soul is not transmitted,
- how is it possible for a soul created anew to inherit the 'Adamic sin'?
Isn't the soul that's created anew clean, pure, untained? If it is, and it is not transmitted, then it shouldn't carry the "Adamic sin"!
- The soul sins through the body with which it is inextricably tied up for the duration of our one life on earth...
- Yes... the soul is not transmitted... it is generated spontaneously at the moment of conception of the fetus...
- Thus, by dint of its tie with the body the soul is able to 'inherit' sin from Adam through an unbroken corporeal line.
So, the soul is created anew, clean, pure, and untainted... it is not transmitted and it is yet able to inherit Adamic sin.
The answer may not be the 'right' one, but I believe it's internally coherent and consistent.