Thanks for the post. I thought about posting something similar, but I did not know how to put it into words. I did study this issue a long time ago so I have no sources - just my memories. I knew that incest did not exist until God gave the command. He created man in such a way that genetics was not an issue at first. He timed the genetic issue perfectly to the time when He gave the command. He created mankind so that at first brothers and sisters would marry and bear children with no genetic problems. He did not forbid brothers and sisters to marry each other at first and it was definitely not wrong to do so. This is how he planned it. It was not wrong until He said it was now going to be wrong. He is the potter. We are the clay. He can create this world and all that is in it anyway He chooses.