Hilzoy at Obsidian Wings combines a wonderful takedown of Charles Krauthammer and George W. Bush (which Brad DeLong quotes extensively) with an equally wonderful non-technical account of just exactly what it is that stem cells promise and that the Bush policy would forbid, an acute analysis of the politics of the problem, and a very sober and reflective meditation on the ethical issues involved. Instead of satisfying yourself with Brad’s except, I strongly recommend that you read the whole thing. It looks as if Somatic Cell Nuclear Transfer (SCNT) ought to be in everyone’s vocabulary; I know it wasn’t in mine.
And while she’s at it, Hilzoy has a very convincing essay on why humans shouldn’t keep other primates as pets, and why, therefore, the interstate traffic in pet monkeys ought to be stopped. I have no independent knowledge of the question, but she sure persuaded me.