I think it gives some support to caution.
>
>On the other hand, we do have reliable hard observational evidence that
>
>1. Zygotes sometimes split
>2. Zygotes sometimes fuse.
>
>And we do have, some of us, a theology that "one soul per person."
>
>Given that data, how can we possibly claim the zygote has a soul? If we
>assert that "God could do it," what is to prevent us from using that same
>argument elsewhere? "The universe was created last Thursday." Hey -- God
>COULD have done it that way!
The importance of the historicity of the resurrection would argue against
creation with apparent history within the past couple millenia. The
difficulties of God being misleading in creating an appearance of history
would argue against creation with apparent history for much longer ago than
that. However, I don't see contrary evidence in the case of the zygote,
just lack of evidence.
To me, the arguement of possible fusion or fission sounds similar
to "we can't tell if it's killing two people or just one person, so it's
OK." If all goes well, a zygote will lead to at least one adult (possibly
in concert with one or two other zygotes); killing at least one human is
wrong.