Image via WikipediaThat's the title of the blog af a chap I used to live with. He did a post a little while ago about an alternative stem cell source, and his thinking on the matter, and we had a bit of a comment box exchange.
He moderates his comments, and I think he decided he didn't want to continue the discussion, but I didn't want my last comment to be lost in the eTher, so here it is:
I think that
it is important to delineate the respective positions. If we're talking about potential human beings that's ethically troubling. If we're talking about human beings, murder is the right word. There's quite a wide range within the word "immoral".
To say that there is no 'magical' moment of conception doesn't strike me as very important. The "moment" of conception can be understood as the beginning of the process, or perhaps the end. By selecting implantation as the 'magical' moment of the beginning of the process of personhood, you're proceeding to answer a philosophical and theological question with a scientific method; strictly speaking, an impossibility, though obviously science can and does aid philosophical and theological enquiry.
With regard to the fertilised egg not being able to be "flushed out", I believe that a baby can be rejected by the mother's body very late term, resulting in a miscarriage or stillbirth. If this were the case, that would make the criterion irrelevant. Moreover, that people die before they are implanted in the womb is no more philosophically unacceptable than that people die at any other stage. Also, I should think that a genome is a distinct individual structure. If so, it doesn't make sense to choose the structures to which you refer in preference to the genome. Neither can the mother's awareness of the pregnancy answer the question. A soul is never demonstrable from scientific observation - the mother's feelings can hardly be a more valid test. Besides, there has already been incredible interplay between the mother and the embryo in conception, where the embryo receives half of its genetic information from her.
I understand that we are currently unaware of what causes the embryonic fission that results in identical twins. This being the case, it may be that the fission is inevitable from genetic or environmental factors. In this case, it wouldn't be unreasonable to assume that there were two souls from the beginning. Or it is possible that there is only one soul at the beginning which becomes two. I gather you don't accept this idea, but I don't see that it's possible to reject the idea whilst maintaining at the same time that Jesus is "eternally begotten of the Father, [...] true God from true God, begotten, not made, of one Being with the Father"; He is of one being with the Father, yet is begotten, a distinct person.
Chimeras would be a separate mystery, but no more impossible than the full humanity and divinity of Christ, the procession of the Holy Spirit from the Father and the Son, the union of the Church as the body of Christ, and that man and wife are "no longer two, but one flesh".
That we don't know how it works can't be an insuperable obstacle. We may think "that a unique genome is insufficient for personhood" but we might also think that 5 loaves of bread and 2 fish were insufficient to feed more than 5,000 people, and yet they weren't. Of course, we know that the second is a miracle - it breaks all the usual rules, but in the case of souls and "personhood", we don't even know the rules unless God tells us.