Currently, BioLogos is hosting interviews with the four contributing authors of the recent book Four Views on the Historical Adam. My belief in a historical Adam who was a recent representative, but not the universal ancestor of, the human race is probably closest approximated by John Walton, whose views are in part 1. Anyone who takes this argument seriously however needs to be informed of the spectrum of views among theologically conservative Christians on this subject.
Part 1 features John Walton, whose views are summarised below:
In my view, Adam and Eve are historical figures—real people in a real past. Nevertheless, I am persuaded that the biblical text is more interested in them as archetypal figures who represent all of humanity. This is particularly true in the account in Genesis 2 about their formation. I contend that the formation accounts are not addressing their material formation as biological specimens, but are addressing the forming of all of humanity: we are all formed from dust, and we are all gendered halves. If this is true, Genesis 2 is not making claims about biological origins of humanity, and therefore the Bible should not be viewed as offering competing claims against science about human origins. If this is true, Adam and Eve also may or may not be the first humans or the parents of the entire human race. Such an archetypal focus is theologically viable and is well-represented in the ancient Near East (p. 89).
More here.