An email (to which I’m adding a couple of links)
As the person referred to by your correspondent (“no more natural”), I wanted to clarify my comment.
I am, relative to most biologists, bioethically conservative. I support a total ban on human SCNT [also known as cloning–RP], and I was not outraged by the president’s constraints on ES research. I understand what is meant by “nascent human life.”
I do confess to being pro-abortion (anti-life, if your prefer), not because I dismiss the value of human embryos but because I find it difficult to quantify their value relative to that of the women who will inevitably die if abortion were again illegal. Please understand that this is not a political declaration. I don’t think that my pro-life friends are cruel. It’s just that I can’t bring myself to join them.
In any event, I thought that Lee Silver made an interesting point. The blastocysts from which embryonic stem cells are obtained are human to the extent that, if not disrupted, they can differentiate and develop into human beings as we all understand ourselves. To the best of our knowledge, the same is true for the colonies of induced pluripotent stem cells described by Yamanaka, Thomson, and their colleagues.
Yet, we are to understand that those who obtain ES cells by disruption of blastocysts are engaging in a species of homicide (meaning, from long human experience, that they deserve execution), while those who isolate ES cells by reprogramming fibroblasts deserve praise.
That is what I fail to understand.
PS Had I known the electronic mail analog of genuflection, it would have initiated this correspondence.
Nice to hear from you. Two points before I get to Silver. 1) Deaths from illegal abortion were pretty rare before Roe, and had fallen quite sharply even before any states liberalized their abortion laws. Such deaths would probably be pretty rare if American states prohibited abortion again. (More on this in the book, of course.) 2) I don’t favor the death penalty, let alone favor it for scientists doing embryo-destructive research.
As for Silver: He doesn’t share the view that human embryos possess any moral worth more profound than skin cells have, and barely understands how any rational person can hold that view. As I’ve written before, I think his inability to comprehend opposing points of view distorts his analysis in many ways.
And I don’t think the equivalence he posits between induced pluripotent stem cells and embryos holds up. He says that the “mouse version of the [iPS] cells can produce a mouse,” but my understanding is that what Yamananka did was to inject those cells into a mouse embryo to see if those cells would play a role in the formation of all the various organs of a mouse. So yes, the mouse iPS cells can be used to produce a mouse, but that doesn’t make them equivalent to an embryo.
I am, however, glad to see that Silver believes that the iPS breakthrough will end the political controversy over stem-cell research, and glad also that he seems to be okay with that.