Mr. George makes many good arguments, but on this one he is wrong. Taking life can be justified. One cannot be pro-life and conclude otherwise. Anyone who, for example, would not sacrifice one person to save ten isn't pro-life IMO. Certainly it would be an agonizing decision, but to do otherwise is moral cowardice.
But the key point is that taking life (or any other action for that matter) must be justified. All outcomes and alternatives must be weighed. IMO, embryonic stem cell research is not justified at this time except on existing cell lines as the president has determined.
I disagree. That way lies polgroms, genocide and the tyranny we face in abortion on demand and unrestricted (except in funding) embryonic research.
The only legitimate reason to kill is to prevent the one killed from killing, and then only if there is no other way to prevent the killing. No "ifs," "ands," and "buts." That is the meaning of "inalienable."
However, we humans are not perfect. We do not have omniscience, and often do not see the present as it is. So, we make mistakes, there is "collateral damage," and even the death penalty and war can be justified (as well as condemned) by our fallibility. Our fallen-ness.
He addresses your hypothetical in the article by making distinctions between social and moral choices one may have to make. ANd he does it quite well.