“Interesting you should ask, ” said I “but we are looking at this story at CBC just at the moment?”
Here, is my answer to the question:
1. If someone believes the account in Genesis 1-5 to be a literal account of six 24 periods etc. Then Cain has to have married and had kids with his sister. This is justified on the grounds that the later prohibition on marrying your siblings came in later (in every culture, not just in Judaism), and the genetic problems with sibling children hadn’t had time to develop yet as these were the first ever humans.
2. If, like me, you see the account in Genesis 1-5 as a parable rather than a biology textbook then it is a different (and less problematic) question. So, Genesis tells us incredibly important things such as a) God made everything, so don’t worship stuff – focus on God; b) humans are made in God’s image and therefore each one is inherently valuable; c) men and woman are both part of God’s image – designed to be complementary to one another; d) the reason the world is in this mess is because humans choose to ‘do it their way’ rather than God’s; e) God loves the world and wants to restore it …….. etc. In particular, the story of Cain and Abel talks about the root causes of hate and murder – in particular envy. What Genesis is not doing is describing a specific historical account of two people.
So, were Adam and Eve (and Cain and Abel – and their wives) a particular Mesopotamian family? Or do they represent the origins of all of us? Adam means ‘Mankind’ and Eve means ‘Living’.
What amazes me going through the story in detail again at the moment, is just how profound, revolutionary and relevant it is, 3000 years after it was written.