Larger Catechism

Q 26. How is original sin conveyed from our first parents unto their posterity?

A. Original sin is conveyed from our first parents unto their posterity by natural generation, so as all that proceed from them in that way are conceived and born in sin.1

1. Psalm 51:5

   Behold, I was brought forth in iniquity,
   and in sin did my mother conceive me.

   Job 14:4

   Who can bring a clean thing out of an unclean?
   There is not one.

   John 3:6

   That which is born of the flesh is flesh, and that which is born of the Spirit is spirit. (ESV)