There are a number of wallets that do or will involve biometrics somehow, but that’s not enough to provide guarantee that only the account owner can execute transactions.
Very high level, transactions on Ethereum, for example, require a valid account, a non-zero balance and the account’s private key to sign the transaction with. I’d argue that in order for biometrics to be involved, a transaction should also require successful proof of biometric identification pertaining to the account owner.
This could be the proof of computation of a successful biometric authentication, in the form of a zk-SNARK. That way, the biometric data that is used or checked against is not revealed, only whether it was successful or not. This is possible because maths (https://crypto.stackexchange.com/questions/60668/can-zk-snarks-verify-the-results-of-turing-complete-computations).
This biometric data can reside on the blockchain or inside your phone’s security enclave (https://www.howtogeek.com/387934/your-smartphone-has-a-special-security-chip.-heres-how-it-works/), for example. Multisig or any other third party authentication data could be accepted as well for the non-human accounts which will outnumber us.
The rant above is about blockchains and IDs in general. I don’t think any existing blockchain does this already or plans for it in the near future. I however think it is possible and even necessary for adoption. Private key management is arguably the hardest thing to comprehend and do right by the average user. Using biometrics to generate, operate and recover accounts needs to happen somehow, perhaps the high level idea above can be a start.
I brought this here because you eat zk-SNARKs for breakfast, lunch and dinner. Looking forward to hearing your thoughts.