This is a much better framework for your question. I think the key to an answer is to ask the question, “Why is bestiality or incest wrong?” They aren’t wrong just because God said so. I suspect that the reasons these things are wrong might not apply to the very special circumstance of an almost entirely unpopulated world.
That’s quite true, but even if we leave the morality of the act aside as I did with the homosexual aspect we are still faced with another genetic quandary.
I don’t know if you’ve read much concerning efforts to save certain endangered species in captivity through intense breeding programs but zoologists and vetinarians are facing a momentous task by the time the third generation is born. Any inbred animal is born with a weaker immune system than a more genetically varied counterpart, and the closer the siblings are the worse the condition becomes. It doesn’t just end with that one animal however, for up to three generations after that again the decendants of an inbred creature are weaker, shorter and have shorter lifespans (aren’t early humans supposed to have lived for centuries?) than their non-unbred counterparts. If humanity was this inbred, it would have died out before the twelfth generation. Just look at some of the genetic diseases infesting European royalty during the 1800’s, and they had a far wider genepool!
We’re not even accounting for physical deformities here that would have made survival difficult if not impossible, but just genetic instability from a shallow gene pool. It’s not just one couple that isn’t enough, one hundred couples would not be able to provide a wide enough genetic base.
At any rate, I’m rather inclined to say that the historicity of Adam and Eve could be completely rejected without touching upon the evidence for the central dogmas of the Christian faith. The Adam and Eve story is a rather peripheral dogma, and in many ways not at all dogmatically held by the Church.
Oh I don’t think protestants like the Anglicans will have any difficulty reconciling things like this with their teachings, after all they’ve never claimed inerrancy and have modified several of their practices when new developments in social justice, theology or the sciences have come to light. The Catholic church however will find some unease explaining this in relation to the Dogma of Papal Infalliability however.
Was it Pius XII who wrote regarding evolution? How it is acceptable to hold to “Theistic Evolution” so long as belief remained that Adam and Eve was the common source of all humanity (I honestly do not recall, but one of them did). To deny the literal parenthood of Adam and Eve of all humanity was clearly labelled a heretical proposition.
I don’t think most non-literalist Christians, or most Cafateria Catholics for that matter will care. It does pose a problem for those who say the Church cannot err in matters of faith, because in this case it clearly has.
No, this is why I like those examples. Because I think it’s likely that there are other extremely good traits associated with same-sex attraction, just like there are good traits associated with both those other conditions. This doesn’t mean that having sickle cell anemia or autism is a good thing.
It doesn’t automatically mean it is a bad thing either as the Church would have us believe. Even if you do not act upon it, it is still disordered, something to be shunned and kept tucked away.
Maybe it doesn’t fit into a cute 50’s American idyll of what makes a perfect family, but no family or relationship is perfect. I know I’d certainly rather embrace the variety within society than enforce a monotone standard.
Damnit, I’m derailing now

. I am not going to let this turn into into an argument on yes/no for homosexuality.
The allegorical interpretation doesn’t involve a short timeframe. On the allegorical interpretation, Adam could have existed 1 billion years before Jesus did – it makes no difference. The allegorical interpretation follows science for its cues about the timeline.
The problem here is that to achieve the genetic diversity from such a small common source of human souls (supposing the inbreds survived) would have taken an exceedingly long amount of time, and while there is evidence (from how our understanding of genetics works and from archeology) that single source theory cannot be and much the support that, there is little or nothing, indeed little more than the Hebrew Bible and Church Tradition that says otherwise.