Why did I go to Fundies Say the Darndest Thing? I hate that site. The whole of it makes my blood boil. A click of their random quote link and look what turns up:
Quote# 26357
Don’t ever compare heterosexual incest to homosexuality! Homosexuality is much worse because it involves two people with the same genitalia! At least incest can be traditional, and involve a man and a woman–a brother and a sister, Just like the children of Adam & Eve! So wonderful and pure of heart! God bless.
Oh my nonexistent god. OMNeG!
Now, if you’ll excuse me. I have to go bleach my brain.
One Minion's Opinion 
That person is just insane.
Of course, they are correct in that if they believe the bible creation story they have to believe that the first humans committed incest and then they must have to convince themselves that it must have been okay with god.
Hmmm … based on that set of beliefs, we are all the result of inbreeding and full of recessive traits.
By the way, I love the “OMNeG”. Can I borrow it?
Yeah, I don’t even need credit. Just tell them where you saw it first 😉
There’s also the interpretation that Eden was just a place on Earth, a gated community if you will, god inspired design or whatever, but after the kickout, there was still the rest of the populated Earth around it so Cain and Abel could take wives from the local village. It always did annoy me how little is included in the bible. If someone tried to write it today, critics would harp all over the crap storytelling and plot holes big enough to drive a truck through. And let’s not even get into deus ex machina tropes…
haha. love it