Man and woman created He them. A man and a woman. That's what is natural.
Eve was made from Adam's rib, making her, most likely, a twin of Adam with just her sex chromosomes altered - but otherwise his genetically identical sister. Then he fucked her. That's what is natural.
"Be fruitful and multiply." Adam and Eve had children. That they were born at all, and escaped hideous birth defects like harlequin ichtheosis (given the genetic consanguinity of their parents), is itself a miracle. Two boys, Cain and Abel, who, because their parents were twins, were in effect parthenogenetic clones of their parents and twins of one another. (One was later killed, which of course made no difference at all to the genetic diversity of the nascent human population, such diversity being zilch in the first place.) Each clone-child nailed Eve, she being the only woman, producing more children of whom they were simultaneously the fathers, uncles, brothers, and twins. Because that's what is natural.
And to this day we all do the same. God having laid down the pattern, we can do nothing else. That is why we resist attempts for fags and lesbos to marry: because it was Adam and his brood of incestuous conjugant-clones, reproducing more like yeast than people - not Adam and Steve.