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How do we know the tumor isn't a person? Maybe it looks like a tumor at first... but after we observe it kinda looks like a person? (This isn't science fiction, by the way.)

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I think this is a little weak, and Vulturesrow isn't stupid. A tumor has never gone on to exhibit properties that most people would deem worthy of personhood, whereas fetuses (sp?) repeatedly have.

I address to you the same question that I asked Vulturesrow: http://forumserver.twoplustwo.com/sh...Number=3996895

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http://dictionary.reference.com/search?q=teratoma
http://www.straightdope.com/classics/a981002a.html

The point of this is that there is something that makes the combination of cells a person.

To answer your questions:

Grant: when a human body has a functioning cerebral cortex.
Revoke: when a human body no longer has a functioning cerebral cortex.