This question always intrigue me whenever i consider it. It has made it difficult for me to accept the Genesis creation account as literal.
It seems more symbolic that a factual blow by blow account of human creation as it actually happened.
Read Genesis 4: 1 - 17 from here, i am not clear of the land of Nod and it's founder and how Cain's wife came to be. Was there more than one creation? or were there another group of people on earth before Adam and Eve were created?
Your honest answers to these questions are most welcome to help throw more light on the creation account.