Via the mighty Instapundit, an AP story on CNN.com indicates that amniotic fluid is a "plentiful source of stem cells." These aren't embryonic stem cells, which theoretically can become any type of cell at all but, in an ethical Catch-22, must be "harvested" from an embryo that is destroyed in the harvesting; but they're promising and apparently very malleable, according to the Wake Forest researchers doing the work.
As a free marketeer, I have to conclude that R&D on stem cells would eventually have gotten to this point - exploring amniotic fluid rather than destruction of embryos, since, if researchers were able to withdraw the stem cells without damage to mother or baby as they say there were, the implication is clear that there are lots and lots of stem cells in there (you're not sucking out a pint or two of amniotic fluid in search of half a dozen cells). I'd assume that an extraction method that amounts to amniocentesis is cheaper than in-vitro fertilization, or in-vivo followed by intact removal of the embryo (I have no idea whether they're proposing that means as a viable stem cell generator).
However, I'm also inferring, rightly or wrongly, that the pressure on researchers to come up with "non-controversial" sources of stem cells is hastening that progression. In other words, if there were no ethical issue with destroying human embryos in order to harvest their cells, we'd just be doing it that way - no fuss, no muss. I'm deeply grateful to those in the public sphere who are bringing that pressure to bear, since the last line of the AP story is, "[Dr. George Daley] began work last year to clone human embryos to produce stem cells[,]" pretty much exactly what those of us on my side of the debate have been fearing and warning against: human cloning - creating a construct that would, if (able and) allowed to grow to viability, be a human being by anyone's definition - with the express purpose of killing that construct and harvesting its parts, further cheapening human life by sanctioning not just its creation (I'll reluctantly give you "potential creation" if there's the usual hair to be split about when a human embryo constitutes a human life) but its destruction at the whim of a scientist.
I'm no Luddite. I believe that private research should go where it will, and that private research is bound to be a more fruitful field than government-sponsored research. But I also believe that bioethics is not just for fun, and that there are important and difficult ethical issues with the intermediate steps between, say, cloning followed by destruction within a few days and in-situ cloning of organs or limbs (the pipe dream I'd love to see fulfilled).
Let me be even more explicit. There's a slippery slope inherent in embryonic stem-cell research: today we create an embryo in vitro and destroy it at, say, the blastocyst stage - what is that, eight cells? sixteen? - in order to take advantage of the total malleability of its cells, a potential that to date remains unrealized; tomorrow, what? If a human embryo created for this purpose is valueless except as a collection of spare parts, what about any other human embryo? and if it's possible, and ethically acceptable, to grow liver cells from embryonic stem cells (hey, it's possible to grow them from adult stem cells - but so far, no go with the embryonic variety, I understand), how much easier would it be, with this valueless embryo, just to let its highly efficient and nearly perfect built-in mechanism work to create a whole liver for you, then harvest that liver, discarding the rest of the spare parts that aren't needed? And while you're at it, why not wait until it's easiest of all to harvest that liver - after the embryo is no longer encased in a uterus? (Of course we'd want to avoid the word "born" there.)
And as I've said before, the logical fallacy of the slippery slope argument is that the dreaded outcome is inevitable, not that it's possible. I think it's hard to argue that such an outcome as I've described is impossible. Likely? Not in a literal tomorrow, or next year; but a whole lot of people in the southwestern United States were in the past, and possibly still are, willing to cross the border looking for medicaments and treatments that hadn't passed FDA muster; where's the barrier to a black market in baby parts? Adult parts are a bit easier to keep track of, because the adult from whom they come has a history; but if the goal is getting a useful part out of a "mature embryo" and then discarding the "mature embryo," all you need is a human broodmare and an incinerator. And an ethical atmosphere that refuses to acknowledge that there's something deeply disturbing about creating human (or potentially human) life with the intent only of destroying it.