[beckerdo]

The best identity I can think of is a hash-code of your DNA sequence. You cannot lose it like an external device, an email, or an implanted chip.

Yes, there might be collisions in a DNA hash-code (such as identical twins), but there can be protocols for that.

[brewmarche]

Another potential problem: https://en.wikipedia.org/wiki/Chimera_%28genetics%29

[explaininjs]

This keeps coming up but is a terrible idea. Your DNA changes every second.