What if someone bribes the person taking the dna sample? Corrupt telecom employees have already been complicit in ID fraud by redirecting SMS traffic to attackers.
How does the business know the DNA used to set up an account for Bob comes from him and not from attacker Bill? They would have to take his ID at his first visit so you’re still vulnerable to ID fraud.
We can argue back and forth but IMO the DNA idea has two problems:
1 It is too invasive as it requires customers to reveal their DNA to the business.
2 It is impractical. Firstly, the technology doesn’t exist. Secondly, it requires a physical visit to authenticate.