This reminds me a lot of a Radiolab episode: http://www.radiolab.org/story/david-and-wire/
I think of the Radiolab story as a cautionary tail, if you try to capture all the special moments, you'll end up preventing them from happening in the first place. Many (most?) people only feel comfortable being themselves when a permanent record isn't being kept. By trying to always photograph your kid, they may start to feel like they have to put up a facade all the time. I know I certainly would.