Yesterday, extending a public debate that I participated in earlier in the week, I criticized some arguments by Reason's Ron Bailey and started to criticize some writings by the Discovery Institute's Wesley Smith. I'm pretty much done with Bailey (see our exchange here), with whom I really don't disagree all that much. But I have more to say about Smith's arguments on the stem cell issue. In my previous post, I left off by objecting to Smith's attempt to create what I view as a false opposition between adult and embryonic stem cell research. There's much more to say here. In particular, I'd like to highlight some important points that the adult stem cell promoters never really seem to acknowledge, but which seriously weaken their arguments. (For a much more detailed discussion, please check out Chapter 12 of The Republican War on Science.)
First off, we already know that from a research standpoint, there are some things that adult stem cells will never achieve. For instance, they'll never be able to teach us about the processes of early embryonic development and cellular differentiation--processes that take place before more specialized adult stem cells have even come into existence. For this, you obviously need to study embryonic stem cells.
We also know that human adult stem cells have been studied for many years, and most of the advances in this area come from bone marrow stem cells. Much of the research here was done by Stanford's Irving Weissman, nowadays a leading supporter of embryonic stem cell research (a fact that really goes to show you that scientists don't think of the two fields as being in opposition). Weissman discovered blood-forming bone marrow stem cells many years before the discovery of human embryonic stem cells by Jamie Thomson at Wisconsin. Those cells haven't been studied nearly as long, and their study has been impaired by politics.
Finally, we know that adult stem cells are harder to isolate in the body, available in smaller amounts, and more difficult to grow. In short, these cells have drawbacks too. It's unfair not to point that out when discussing this issue, but the adult stem cell promoters never seem to do so.
But enough with the adult stem cell issue. Smith also uses other questionable science-based arguments to denigrate embryonic stem cell research, such as the constantly repeated Alzheimer's attack:
If stem cells have little 'practical potential to treat Alzheimer's,' why do proponents of cloned-embryo research continue to invoke a cure for Alzheimer's in their sales pitches?
In my view, those who attack embryonic stem cell work over the Alzheimer's issue are using a very selective description of what this research is really all about. Embryonic stem cell research isn't merely being conducted so that we can learn how to grow specialized tissues that can then be used to cure diseases through transplantation. It involves much more than that.
Because it is a complex brain disease, Alzheimer's probably won't be treated through stem cell transplantation. Smith is right about this. But new insights into the nature of the disease could nevertheless be gained through embryonic stem cell research or the related therapeutic cloning research. If we had embryonic stem cell lines with the genetic signature of Alzheimer's--lines that would probably have to be developed via somatic cell nuclear transfer of genetic material from an Alzheimer's patient's cells into an enucleated egg--we could not only study how the disease develops, but potentially test new Alzheimer's drugs on these cells.
So it's not wrong to talk about Alzheimer's in the context of embryonic stem cell research, as long as you know what it is that you're talking about. To be fair, perhaps some advocates for the research have been incautious about this. But those who use the Alzheimer's issue to attack embryonic stem cell research are equally incautious, probably more so.
Finally, Smith has also raised questionable safety concerns about embryonic stem cell research. For example, in the course of praising umbilical cord stem cells he wrote the following:
Unlike embryonic stem cells, UCB stem cells don't cause dangerous tumors. Moreover, they are easier to tissue-type to prevent rejection than are bone marrow stem cells. And here's another big plus: This research is utterly uncontroversial. No embryos are being cloned. No embryos are being destroyed.
The claim that embryonic stem cells will cause tumors, or teratomas, has some technical truth to it but really amounts to a scare tactic. I recently had the opportunity to discuss this topic with Robert Goldstein, chief scientific officer of the Juvenile Diabetes Research Foundation. He explained to me that while embryonic stem cells have the potential to form teratomas (due to robust growth and differentiation into different cell types), well characterized lines can be observed to make sure that they are mature and no longer behave in this way. And of course, no one is going to inject someone with cells from a line unless that line is known not to produce teratomas. To do otherwise would be completely unethical. So this is not a practical problem.
So, when it comes to Wesley Smith's recent writings in the one area where we really overlap--embryonic stem cell science--I'm fairly troubled by them. In my view, it's fine to oppose research on ethical grounds, in the sense that ethical positions are debatable and everyone's entitled to his or her own perspective. But scientific information shouldn't be molded to make one particular ethical perspective seem stronger than it otherwise might.
To be fair, Smith's arguments on these topics--the promotion of adult stem cells, the Alzheimer's attack, the tumors argument--are broadly consistent with the arguments of many other anti-research conservatives. It's not like he's the only person doing this.
