I would be remiss if I didn't address the latest stem cell news, since it's already all over the place. An article from today's issue of published in advance online yesterday by Nature describes a technique for deriving a line of human embryonic stem cells by removing a single cell from the eight-cell blastula (created for in vitro fertilization). According to the paper, the blastula can still be implanted and allowed to grow and develop normally, without any apparent damage to the embryo. Not surprisingly, the press has painted this as a potential solution to the "moral reservations" behind Bush's embryonic stem cell research restrictions. Dispatches from the Culture Wars and Gene Expression have already chimed in, and Jake of Pure Pedantry offers a lucid overview and critique of the article.
The reaction within the scientific community has ranged from cautious optimism to outright skepticism, and I find myself somewhere in the middle, leaning toward the side of the skeptics. Jake's review gives us plenty of reasons to be cautious about taking the results of this paper too far. In particular, the health of both the embryos and the stem cell lines have not been fully evaluated, and this technique requires the use of mouse feeder cells, limiting the potential therapeutic potential of stem cell lines derived in this manner.
When it comes down to it, this technique appears unsatisfactory for ending the current debate either way you look at it. If the technique is validated, and it can in fact produce 100% totipotent embryonic stem cell lines without harming the original embryo, this would mean that the cell used to generate the stem cell line would itself be capable of developing into a human embryo under the right conditions. Since the opposition to embryonic stem cell research generally takes the very narrow view that a fertilized egg is the moral equivalent of a fully grown and developed human being, this probably won't due much to appease these opponents. Remember, these people prefer to let the extra embryos generated by in vitro fertilization procedures go to waste, instead of using them to generate much needed human embryonic stem cell lines.
On the other hand, if the technique is demonstrated to be significantly less effective than traditional means of harvesting human embryonic stem cells--as seems to be the case--then it is not an acceptable alternative. Although this method shows more promise that some of the other alternatives previously proposed, including creating genetically-altered embryos incapable of completing development, it remains imperative that we continue to try to make the case for the accepted and proven techniques of generating human embryonic stem cells. Instead of giving in to religious zealots, we should instead make sure the ethical debate is fully informed.
I described one generally underused points of information that is not widely used in my recent review of Coming to Life:
Nüsslein-Volhard notes that policies on human embryonic stem cell research vary widely worldwide, and many are based on the ill-conceived notion of life beginning at conception. Instead, she argues that implantation of the embryo in the uterus marks a much starker developmental landmark (a previously independently developing embryo suddenly "placing itself in direct and immediate cell contact with another individual"), and without this step, embryonic development cannot proceed. Although life is a continuous cycle--making any definition of the "beginning of life" fundamentally flawed--since the derivation of stem cells from an embryo takes place before implantation, this should prove the "moral concerns" (a.k.a. political pandering) guiding current policy unfounded.
Although many will probably claim that the recent study is the solution to our stem cell debacle, we should only be cautiously optimistic, and we shouldn't let this distract us from the push to end our current unreasonable restrictions on federal funding for human embryonic stem cell research.
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It's funny that scientists are constantly trying to convince people of alternative times that life "begins". Conception vs implantation vs neural tube formation vs movement vs viability outside the womb. It's just nuts. From a scientific perspective there is no correct answer to this question except that life doesn't begin. And I think this is the first time this point has been acknowledged by a scientist arguing the ethics of ES cells. I yell about it all the time but it never seems to catch on.
Life began a long time ago, billions of years, and since then has been a continuous process. Sperm are alive, eggs are alive, embryo is alive etc. The question that people are trying to address by these discussions isn't really whether or not life begins, because it doesn't, but rather when "ensoulment" occurs, or from a secular point of view, when do we care? I think she's started her argument correctly but implantation is still to early to care.
These discussions over life beginning are fundamentally relgious and irrational and scientists shouldn't even acknowledge their relevance. Makes me a bit nuts. Ensoulment, what a load of crap. Like an omnipotent deity can't figure out which embryos will make it? Or limbo is full of human caviar? These people doen't give their god enough credit. And, when you look at the history of the idea it's based on a terrible idea of biology, that the sperm carried the entire individual (the drawings used to show a baby encapsulated in the head of a sperm) that would then merely grow, not develop, into an infant.
Anyway, I salute Nüsslein-Volhard for making this point, I think it's the most important one in this debate, and the beginning of a real scientific discussion of the relevant ethics.