[agrace]

Suppose we take a fertilized embryo, allow it to divide once, and then separate the two daughter cells. This is almost the same as what happens to produce identical twins. We implant one embryo, where it goes on to be born.

Can we do this? What do you mean by "almost"? Will this action in fact produce two embryos? I truly don't know, do you? If it can't, your question is a bit of a strawman.

That said, I'll assume the premise is valid and answer your question. You said

If you think we have destroyed a human life, then explain why, since we have the same human being we would have had had we done nothing.

But that's the thing - in the scenario you described, we DID do something. A second life was formed. There's no going back, at that point.

[HayekRocks]

But that's the thing - in the scenario you described, we DID do something. A second life was formed. There's no going back, at that point.

OK. Then suppose we split off a cell at a later stage. Is a human life still formed?