The commonly accepted view in the Catholic West (as opposed to the Catholic/Orthodox East or the Protestant West) is that Original Sin is the privation of sanctifying grace[2] in consequence of the sin of Adam.
In other words, it's not an inherited genetic disturbance; rather, at the moment you were conceived you were lacking in a spiritual quality which God did not gift to you in view of the disobedience of the first parents of the human race.
In any case, this could quickly get far afield from the bounds of an HN-ish discussion, but I did want you to be conscious of the fact that your notion of Original Sin may be unnecessarily limited to what amounts to a caricature.
[1] http://oce.catholic.com/index.php?title=Original_Sin
[2] http://oce.catholic.com/index.php?title=Grace#II._SANCTIFYIN...