Adam and Eve had more sons and daughters later who fucked each other(incest shit acceptable then)...Noah's Ark was another story..and another
Genesis 19:36-So they made their father drink wine that night also, and the younger arose and lay with him; and he did not know when she lay down or when she arose.
36 Thus both the daughters of Lot were with child by their father.
37The firstborn bore a son, and called his name Moab; he is the father of the Moabites to this day.…