That's the question posed by Brian LePort:
[I]t seems among evangelicals there are many who would say that it doesn’t matter if the "sun stood still" as Joshua led Israel in war or if Jonah and Job are real people, but the Exodus and the Resurrection have to have been real events. One reason why I think the debate over the historicity of Adam and Eve has been so intense is because Christians are wrestling with the implications of this teaching. What would it mean to Christian anthropology, gender and race relations, marriage, our doctrines of sin and atonement, and even eschatology? What would you argue must have happened?
Tom Verenna proffers a guess:
The difficulty in this question is in deciding, for yourself, which is more important: the historical truth or the theological truth? I am certain that early Christian minimalists didn’t care for the historical reality of the Gospels–if they did, there would not be four canonical ones (and there certainly would be dozens of noncanonical ones!). The theological message above all else seems to have been more valuable a truth and thus why we have multiple theological messages in the narratives (even between the epistles and pastorals). The historical value of the text was only useful when it suited the functions of the theology.
Gavin R turns the question into a true/false quiz.
The Dish 