Scriptwriter Mike Rich said he wanted the story to flesh out who Mary and Joseph were and what emotions they must have felt as they faced the immense responsibilities God entrusted to them...However, he said he felt the story of the Nativity had always been presented as an "event-based" story: what happened and when, with little about how the protagonists lived their faith. After months of research and input from religious scholars, Rich started writing what he called "a character-based story." Rich, a nondenominational Christian from Beaverton, Ore., said that even though his story was speculative he still sought to keep it faithful to the spirit of the biblical account.
Hardwicke said that when she first saw the script's title she thought it would not be interesting because she knew the story of Jesus' birth "backward and forward." But she said she was "intrigued because the writer got inside the heart and soul" of the characters...She said that in directing the movie she tried to build on making the characters seem real on the screen so people could easily identify with them and see how ordinary people, like Mary and Joseph, were able to take such a huge leap of faith.