The Curious Case of Benjamin Button

What is this movie trying to say?

Beyond the simple (though certainly substantial) message that the trailer hits us over the head with (by quite overtly stating it) that life can only be understood looking backwards but must be lived moving forwards, what can we seek to understand from this tale?

The part of the premise that gives me pause, and I'll leave it at this for now, is the nature of the relationship between Pitt and Blanchett's characters. Wrap it up in hollywood trimmings and drapery all you like, but is this not a pedophilic relationship? Are we supposed to sympathize and identify with an old man who pines for a young girl? Similarly, the other end of the logical conclusion would have us ask what happens when she becomes old and he becomes young? Is it a total role reversal or do gendered double standards change anything?

Something to ponder, but no real conclusions can be drawn without seeing the movie.