There are identical twins out there whose parents confused one with the other and now they living their life with the name of the other sibling, never noticing because it doesn't make any difference.
There was a case in my country where two babies were swapped at the hospital. One mom had the presence of mind to take pictures right after giving birth, which she used to prove that she was given the wrong baby (hers had a full head of hair). The other parents were blissfully ignorant of the fact there was a switch.
