The Unfulfilled Promise of an Offspring

In chapters 15 and 16, it seems that both Abram and Sarai come up with man-made ways to bring about the promise of offspring. I read this proposal of Sarai as an outworking of Genesis 3 16, your desire will be for your husband and he will rule over you. In a very subtle way, Moses seems to be presenting Abram as no better than Pharaoh because he's doing the same kind of thing that Pharaoh did with Sarah.