In theory something bitcoin-like can be done with the parts human can regrow (like hairs) - they all have same "seed" - DNA, but they all unique (i.e. hair = bitcoin address, DNA = your public key, but something still should act as your private key and that is another dead end).
I don't think the majority of the people in this thread actually understand the problem correctly. When you provide your hash of whatever ID system you come up with to the blockchain,
the blockchain has to be able to verify the correctness of this hash, which it cannot possibly do without a central authority.