Not “who”, but “what” is a legitimate question. Is an egg fertilised by only one parent and genetically modified to lack any higher brain structures (and there

Not “who”, but “what” is a legitimate question. Is an egg fertilised by only one parent and genetically modified to lack any higher brain structures (and therefore any function of mind) still a “human being”? Can anyone who answers that question with “yes” justify it without reference to supernatural beliefs?