Being alive is a necessary, but not sufficient condition to exercise rights. We don't give infants the right to vote. And [link|http://www.straightdope.com/mailbag/mcemeteryrights.html|some rights] exist even for the dead. So saying your version of humanism implies a right to life isn't a very satisfying way to address the question.

You really need to define "life" in this context. Is it human volitional motion? Response to stimuli? Breathing? Heart beat? Electrical activity in the cerebrum? Body temperature above 95 F? Cell division?

Can a person over 18 forfeit their life to the state as a result of a trial or a decision by a representative of the state? What about a person under 18? What about a fetus?

I don't think you can come up with a comprehensive one-size fits all definition that wouldn't result in a police state. "I'm sorry that some blood cells escaped my body and died, officer. I accidently skinned my knee. It wasn't intentional." :-/

If a fertilized egg is a "life", then why isn't an unfertilized egg or a sperm cell? If it is "life", with as much meaning as that for a person over 18, then whose responsibility is it to protect those rights? How intrusive should that protection be? And what about vestigial (or [link|http://en.wikipedia.org/wiki/Parasitic_twin|parasitic]) twins? Do they have the same rights as their host?

As much as you seem to want it to be, modern society isn't black and white. Everyone who disagrees with you isn't stupid, evil, and wrong (as you too often imply or even state directly).

Cheers,
Scott.