I just came across this anonymous Christian blog, who in 2014 posted his/her interpretation of Adam and Eve which is basically the GAE idea.
At this point it’s important to remember what the Bible does NOT say about Adam and Eve. These are common but unfounded assumptions that people often read into the story, assumptions which in fact cannot be true based on our understanding of history and science. So: the Bible does NOT say they were the first members of the species Homo sapiens sapiens . That is a designation that did not even exist until modern taxonomy, and it would be ridiculous to use it in our interpretation of Genesis. The Bible also does NOT say that they were the only anatomically modern humans God created. It actually often hints at the existence of other humans outside their family. The Bible only says that Adam and Eve were the ones to be created in the image of God. I am here making a very clear distinction between biological humans and spiritual human beings. Biological humans evolved around 200,000 years ago, according to our current best estimates, but Adam and Eve lived around 6,000 to 12,000 years ago, depending on how you interpret the genealogies. Adam and Eve were not the first biological humans or the only ones that lived in their time, but they were the first spiritual human beings - full, biological humans who were also ensouled bearers of the image of God.
Sometimes he sounds eerily like Josh!
But how could Adam and Eve be ancestors to all the humans alive, if they only lived 6,000 to 12,000 years ago? Isn’t this all rather contrived? Not at all. It is actually perfectly natural for a population to have a relatively recent common ancestor. It would be contrived if such a common ancestor did not exist - That would basically mean that the “population” was in fact two or more populations. And the scientific time estimates for the most recent common ancestor (MRCA) for all humans is shockingly recent - possibly as little as 2,000 to 4000 years ago by some estimates. Needless to say, this timeframe agrees remarkably well with the biblical timeframe for Adam and Eve.
Lastly, there is the question of when, exactly, Adam and Eve became the common ancestor to the whole world. As I mentioned above, I believe that every person in the Bible, and everyone that we have a written historical record of, is a descendant of Adam and Eve. This means that their descendants had to spread to each of the major civilizations before it began to flourish, and probably spread out to nearly everywhere by the time of Christ. This is a strong constriction which forces back the lastest possible date for the common ancestor. An important reason that the MRCA of humans living today lived so recently is the relative ease with which we could travel to, colonize, conquer, and trade with the people living in far off places. This mixes the people of different lineages and allows quicker divergence from the MRCA. But the MRCA of the people living in the first century might have lived quite a bit further in the past, as the starting point is pushed back 2000 years, and travel was more difficult. But I believe that even under these constraints, Adam are Eve are sufficiently old enough to be the ancestors to all of humanity.
He even makes a genealogical diagram similar to the one in Josh’s article in PSCF.
He also talks about the people outside the Garden:
You may object that I have divided the human race into two classes: “spiritual human beings” and mere “biological humans”, which I suppose can be termed “mere animals” if one were in an inflammatory mood. I will come back to this point later, but for now, it is of little practical importance. Everyone you meet, every individual you’ve read about, everyone that appears in the Bible or in history, and every person that you’ve ever felt a human connection to, are all descendants of Adam and Eve, and all spiritual human beings. This distinction therefore cannot be used to justify any kind of discrimination or oppression.
A little contrast to Josh, though, is that he emphasizes that in his opinion the image of God spread through humanity through family relationships:
This is clearly spelled out in John 1:13. Being the “children of God” does not depend on “natural descent” or a human parent’s biological decision. Now, there can be some hair-splitting of the difference between “children of God” and “image of God”, but overall I believe that this is fairly convincing evidence that biological heredity is not essential for our spiritual identity.
All these things suggests that the image of God is transmitted, not through purely biological means, but through relationships - in particular, the kind of nurturing, mentoring, teaching, and influencing relationship that a father would have with his son, born out of love. This most often happens between parents and their biological children, but the biology only exists to serve the relationship. God, as the one from whom all fatherhood on heaven and on earth derives its name, saw fit to design our biology to enable the relationship, so that we could better understand and draw near to him.