God created Adam and looked down upon him and saw that he was lonely and that he needed a help mate. SO he approached him and spoke.
"Adam, this is God. I want to give you a help mate to go through life with. Her name shall be Eve. She will never talk back to you, she will serve your needs without complaint. You can do as you please and she will remain happy all the time. She will always love to pleasure you, in ways that you yet have not even become aware! And for this all I ask of you is that you give up one leg and one arm"
Adam pondered what he had heard God say to him and then he looked up to the heavens to speak.
"Well God, what would I get if I just give up a rib?"