It's not a miracle, it's just biology. If you can generate a whole, adult organism from a single fertilized cell (which them becomes a zygote, and then an embr

It's not a miracle, it's just biology. If you can generate a whole, adult organism from a single fertilized cell (which them becomes a zygote, and then an embryo), why can't you also regenerate missing pieces? Obviously, for organisms that can't (like humans), either something is broken, or we lost the ability because there was an evolutionary advantage in doing so (perhaps cancer protection?). It should be entirely possible to change the way our bodies work to re-enable this regeneration, though it would probably come at some cost. However, since we're no longer primitive cave dwellers without modern medical care, who had to constantly worry about infection killing them, that cost can probably be easily mitigated.