According to the bible, God created Adam and Eve about 6000 years ago...Lets think about some maths:
Two people multiplying to 6.5 billion in 6000 years. Ignoring the whole flood thing, how many children would eve had needed to give birth to to allow for both the genetic variation and the current population of the planet?
Has anyone ever thought about this before? I might attempt the math myself sometime if no one has.
It would have had to have been either his sister (yum) or a niece-- maybe Abel or Seth's daughter, which is to say one of Adam and Eve's granddaughters (... yum). Unless of course he met her outside the first family, in which case she's probably one of the neanderthals (yum?) that humanity would go on to wipe out.
See my reply to Dale above RE: my favourite Cain's wife explanation.
Granted, much of Genesis is fanciful invention. However, the Law of Moses established the basis for the most robust form of governance in all of human history. It lasted some fifteen hundred years. Of necessity, in America and elsewhere, the profoundly difficult problem of good governance must be taken up anew, a fact that Americans will shortly be sent to school on. That will require abandoning seeing the Bible as a rule book and beginning the search for what deeper meaning can be found there. To learn more, read my book, Dark Knowledge.
The religion is not the original motivation here, but patriarchy and grand societies are. The patriarchs of Egypt, in order to rein in their vast populations, needed to develop new systems of governance, this is when patriarchy developed our modern sense of monotheism, as a political tool of fear and control, in order to dominate their large and growing civilisation. Without the ascent of patriarchy in the world's biological order, monotheism would never have been invented. For more on this topic, watch Gwynn Dyer's (Canadian historical journalist) "What's an Atheist to Do?: Gwynne Dyer's The Gods of Our Fathers"
One thing I've been thinking about is that, if we all come ultimately from the same woman (aka "Eve" but not the Biblical Eve), and if incest and inbreeding are bad, doesn't that explain a lot about us?
The biological eve is a theorical person that every human is genetically decended from, it doesnt imply incest as such a person would be surrounded by her local population and that entire population would have controbuted genetically to the future offspring. However stories like adam and eve and noah's ark force incest as the only logical outcome of the situation.
From here in Wikipedia (emphasis mine):
"Two pieces of the human genome are quite useful in deciphering human history: mitochondrial DNA and the Y chromosome. These are the only two parts of the genome that are not shuffled about by the evolutionary mechanisms that generate diversity with each generation: instead, these elements are passed down intact. According to the hypothesis, all people alive today have inherited the same Mitochondria from one woman who lived in Africa about 160,000 years ago."
It's a hypothesis, I guess, but I think it's fairly widely accepted.
I think it is worth mentioning that the mitochondrial DNA is passed down from Mother to daughter, so other mothers had sons who then mated with those daughters... I think that's how it works...
You cannot have a human phenotype with all the alleles possible. My understanding of genetics is that you can only have a few loci with different alleles (eg, black hair, brown hair, blond hair, etc). To have all the genetic variation we have today would mean that adam and eve had dna that was very different that ours today.