Board Thread:Show-Related Questions and Answers/@comment-27308670-20160802203731

Rumplestiltskin: Funny you should ask. (Summons up a contract.) Can you read? Cora: My firstborn child?

This quotes are from "The Miller's Daughter", so Rumple is asking for Cora's first born in exchange of teaching her to make straw into gold. At this point Zelena is already born. So Rumple is asking for someone that already exists. But even that Cora's first born was already born, Rumple wasn't asking for that baby. He wanted Regina. Of course that Cora changed the deal for their first born together, but still, since Zelena was already alive, before the deal was changed, Zelena should have been given to him.  