[alasdair_]

>Definitely better

You can change a security question. You can't change your DNA.

Biometrics are usernames, not passwords.

[blitmap]

I thought you could "replace" your DNA with a bone marrow transplant? I am most definitely not a scientist.

[jazoom]

You could replace the DNA of your bone marrow that way, and maybe the DNA of any blood cells that happen to be made by that bone marrow, but most of your body will still have the old DNA.