Actually incest has played a big part in humanity for millennia, most medieval royalty was surrounded by incest, though not necessarily siblings (though I can't rule that out, you can never be too sure back then) which put together makes up about 1,000 years of recorded history for us. Also adding the Adam and Eve Myth (or legend, depending on your religious views), that is spread by a few of the popular religions that are considered to be the moral back bone of society. The story states that humanity, in the beginning, started off with only two people. Thus meaning that the children had to either procreate with each other or their parents (I'm not too sure on the actually story) to create a world full of humans.
So with a world full of Catholics, Christians, The Jewish and Muslims (Those are the only four that I can have some degree of certainty that they acknowledge Adam and Eve) it is safe to say that the normal person would not see incest as immoral or obscene.
Plus going by science, incest is only wrong if you procreate with your family members due to the increased possibility of genetic inconsistency that may cause issues later in the child’s life. This means that same-sex incest is in no way harmful due to the inability for either participant to get pregnant.
Sorry about this little post, I got irritated by the guy with the long name that I cannot bother to type because I am irritated (just go back half a line to find out why) and tired. It most likely does not contain proper sentence structure and thus I assume that each point might not connect well.
Oh and saintl1 I think it would be safe to assume that they will eventually release this as a DVD. No matter what the industry is, you can alwasy sell contriversy for a lot.