On a random thought, is it possible that the story of Adam and Eve is merely that - a story? Or that out of all the people that God made, he chose to tell the story of the lives of one specific couple?
Take it this way - God chose only to tell the story of Israel. He doesn't say much about the other nations, except where their lives intersect with that of His chosen nation. And yet we know that there were many other nations and there were many other lives and many others who had chosen to follow God in their own way and culture. Why not the same with Adam and Eve?
Because even before the story of Adam and Eve, God had already said that He created man in His image, male and female.
Gen 1:27And God created man in his own image, in the image of God created he him; male and female created he them.