No, we didn't think that was possible either.
Everyone remembers the start of Fallout 3. Your character being born, you choosing his/her name & stats, and seeing Liam Neeson for the first time. You don't play the game as a baby, but as an adult via the magic of flashforward.
Unless you're Bryan Pierre, who utilised a nifty glitch to escape the vault before getting to the growing up part. Not only that, but he even played the entire game, and finished it, using the glitch.
How did he do that, you ask? Fallout 3 actually doesn't have a baby model, so, to the game, you're just a very tiny vault survivor. This results in hilarious encounters of enemies missing their shots, but is equally frustrating when you can't reach certain objects.
Here's the first part of his playthrough, the rest is available on his channel.