Are you talking about the book? My wife read it and said it wasn't very good. The movie was great but I wouldn't call its gritty, near-future dystopian setting very cyberpunk either. Cyberpunk is generally "high tech, low life" but 'Children of Men' doesn't really have high tech. 'Minority Report' is more cyberpunk than 'Children of Men' (but still not that cyberpunk).