We at TCC are not big fans of George Bush. In spite of his purported Christian sympathies, he violates many basic tenets of Catholic teaching, including capital punishment, unjust war and solicitude toward the poor. I won't even get into his political sins, which are not appropriate for this venue.
But when it came to stem cell research, W got it right. The Church teaches that life begins at conception. So far, I have not heard a single argument that persuades me to think otherwise. So if human life starts at conception, growing a fertilized egg with the express purpose of obtaining stem cells from it is immoral, even if the cells could be used to save lives.
An analogy. Your mother has a rare kidney disease and needs a transplant. You know (don't ask how, this analogy is hypothetical!) that Mr. Smith, your across-the-street neighbor, has a kidney that would match your mother's. Is it moral to ask Mr. Smith to cross the road, fully intending to run him over so you could harvest the kidney for your mother? Of course not.
The only leg that the stem cell supporters have to stand on is their insistence that a fertilized egg is not a human being. But their argument is based on a belief, just like mine is. Science cannot prove that a fertilized egg is not human, or that an embryo only becomes human after a certain number of days or weeks. If science could, there would be no argument. But it can't. SO given the lack of proof, it is prudent to give the embryo the benefit of the doubt.
If I found a large box in the middle of the woods, would it be moral to shoot a bullet into it? What if a child was hiding under it? What if a friend said, "I am sure the box is empty" -- would you shoot? What if your friend was wrong? Or crazy? Or homicidal? What if you yelled" Hey! Is there anyone under the box?" but got no answer? Would you shoot? Perhaps a deaf child was hiding under the box. Perhaps a frightened child was under there.
The point is this: until you could lift up the box and ascertain that there was no child under the box, it would be immoral to fire a bullet into it. You would have to act as though there was a child under there. Similarly, the current state of science does not allow us to determine with certainty whether there is a human being in an embryo. Until it can, it would be prudent to act as though there was a human being "in there."
God help me to say it: Bush was right to oppose further stem cell research. It is immoral to destroy what might be (and is, according to Church teaching) a human being, even in an effort to save others.