I think a functioning human brain capable of consciousness is required to earn the title of human. And I'm perfectly ok with outlier cases or fringe examples being adjudicated by either biological family, legally appointed guardian/owners, or medical professionals. Just a personal opinion. Maybe that is why I do not understand this debate very well, because according to my own definition, there is no moral/ethical/philosophical difference between flushing a zygote and flushing the contents of a toilet bowl.
I know when my ex-wife got pregnant, however, the topic of abortion was brought up. I found I was offended by the idea. Not because of anything ethical, simply because I had thought that the basis of our partnership entailed starting a family, and somehow the mere act of bringing up options to back pedal from that goal wasn't pleasant. We decided to have the baby, and I've been happy about that decision every day of my life since, however, I am still very much of the opinion that the alternate choice was just as morally and ethically sound, it would have been a choice to not finish creating a life, it wouldn't have been a choice to take a life.
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I am Ignostic.
Go ahead and define god, with universal acceptance of said definition.
I'll wait.