I just rewatched the 22 minutes of gameplay from E3 or whatever this year for Fallout 4.
Its pretty obvious that the main character is probably an android, imo.
You start in 2077 and set up your character and stuff, then you race to the vault because the bombs are falling, then the bombs hit as you're entering the vault, then you wake up outside the vault 200 years later.
Boston is where MIT is, which is the Commonwealth/Institute, which trained House in the past and which was the source of the Replicated Man questline in Fallout 3.
Not a lot else except cryogenic freezing explains why this person who was alive in 2077 wakes up in 2277 on top of the vault.
That's my theory going into the game at this point. You'll get some big reveal at some point that you're a replicated man who has his memory implanted from like records in Vault 111 or some shit. Seems plausible at least.
Anyway, rewatching that 22 minutes of gameplay has me so jazzed for this game. Less than two months away now, which is good.