A Ship of Theseus concept where individual neurons are replaced one at a time with a nanotechnological functional equivalent.
Are you still you?
I’m not a neuroscientist, but as far as I know we already do brain operations where the patient is conscious. Couldn’t a gradual-replacement procedure leverage that fact? And if we left multi-year gaps between each swap, friends and family would effectively be running a long-term Turing Test . Wouldn’t that count as evidence for preserved identity?
Regarding the case where both “digital gametes” originate from the same one, I think it can reasonably be viewed as a digital analog of parthenogenesis that already exists across biology, from lizards and sharks to certain birds.