Short of a DNA swab it would suffer from similar issues as password+2FA and can possibly be used as an attack vector in its own right, e.g. Bitcoinalk password reset via e-mail can be used to by a hacker to get into your account if it's easier to compromise your e-mail account first.

Let's face it, any security measures have limits and it's just a matter of how badly someone wants your account. Password+2FA is good enough for a Bitcointalk account. Password alone - maybe not. Account recovery - meh, its reputation is likely shit anyway if it got compromised so might as well forget it.