The Original Sin Doctrinaires say that because Adam sinned, we have sin from our creation; we inherit it through our flesh.  They use Psalm 51 and verses from Paul's letters to justify this.  This doctrine however, is first of all, in violation of the principles the Lord laid down in Ezekiel chapter 18 which says that "if the fathers eat sour grapes, the children's teeth will NOT be set on edge." 

Secondly, you have to (a) admit then that Jesus inherited this sin through his flesh, thus denying that he is Messiah since how can someone who is sinful save you--classifying you as antichrist for believing this, or (b) claim that Jesus avoided this sin by not coming in the flesh or in some other kind of flesh--also making you antichrist.   (See the definition of "antichrist" laid down in 1 John.) The only way to avoid being antichrist is to confess (a) Jesus is Christ and (b) that He came in the flesh.  And you can only do this by rejecting the false doctrine of original sin.