The screenwriter had an interview with comingsoon.net awhile ago. He had this to say about the film:
CS: How many scripts do you generally write a year and are you able to work on more than one of them at a time?
Roth: No, I don't usually, but what happens is they start piling up and they're in different stages. Like for instance "Benjamin Button," I had rewrites to do and they're filming it right now, so that one's basically done unless they need rewriting while they're filming.
CS: Last year, you had "Munich," this year you have "The Good Shepherd." What is it about these complex, research-intensive projects that interests you?
Roth: I did this "Benjamin Button" one that I don't think you will find [to be] that. It's more fanciful in a way, and hopefully, it will be emotional.
CS: For that Fincher film, you came on board after a bunch of other writers.
Roth: Well, "Benjamin Bunton" was slightly different, because I just took permission to start from scratch. I never read anything that anyone else did, and any resemblance would just be purely coincidental. The only thing that remains is the names of the people in the F. Scott Fitzgerald [book]. The heart of it is about a guy who's aging backwards, but other than that, I just went "Page 1, this happens" and none of it's from the story or anybody else.