Yes, I believe this is a key verse for them:
Gen 3:13 : And the Lord God said unto the woman, What is this that thou hast done? And the woman said, The serpent beguiled me, and I did eat. KJV
Adherents say that "beguiled" means seduced sexually, and that "I did eat" (or partake) means they "knew" each other. But as IT noted, Gen. 4:1 clearly blows this out of the water.
Interesting.