Posted by Russell Korobkin:
Stem Cell Advance Raises New Questions:
http://volokh.com/archives/archive_2009_07_19-2009_07_25.shtml#1248384847
Two respected scientific journals today reported that Chinese
researchers have created baby mice out of induced pluripotent stem
cells ("iPSCs"), an advance that raises difficult ethical questions
and could reignite the culture-war battles over stem cell research
that have subsided over the last two years.
Many conservatives oppose human embryonic stem cell (hESC) research,
and President George W. Bush severely limited its funding, because the
five-day old embryos (called blastocysts) that are used are living
organisms and, if implanted into a uterus, could mature into people.
Although President Obama lifted the Bush funding restrictions, the NIH
released new guidelines that are still solicitous of the discomfort
many Americans feel about using blastocysts for medical research: the
Obama administration will fund such research only if the blastocysts
used are "extras" created in in vitro fertilization clinics and would
be otherwise be destroyed anyway. Want to create a blastocyst in a
test tube in order to produce stem cells? Don't look for federal
funding, even from a Democratic administration.
The new federal regulations have provoked relatively little media
attention, in part because most scientists have believed for the last
year or two that hESCs are a transitional technology about to be
overtaken by a newer one. In late 2007, scientists succeeded in
reprogrammed ordinary adult skin cells (and other types of adult
cells) into cells that seem to behave, for all practical purposes,
like hESC cells. Scientists still aren't sure that these new iPSCs
will behave exactly the same as hESCs for purposes of medical
research, but the available evidence looks good, and iPSCs have a
number of advantages over hESCs. They are much easier to produce than
hESCs, and unlike hESCs, iPSCs offer the potential of allowing
scientists to one day use a patient's own cells as the basis for
creating a stem cell treatment that would not create problems of
immune system rejection. And, of course, iPSCs do not come from
embryos that could develop into a person, so iPSC research has met
with widespread approval by conservatives who oppose hESC research.
But what now? If an iPSC can develop into a baby, just as a blastocyst
can, why is it any less troubling to use iPSCs for medical research
than it is to use hESCs? One possible response is that iPSCs can't
become people without human intervention, but the same can be said of
the blastocysts created in test tubes that are used for hESC research,
which need to be placed in a womb. A difference between iPSCs and
blastocysts is that the latter have a new, unique genome, whereas the
former have the same genome as their donor. But we don't think
identical twins are any less morally valuable because they lack a
unique genome, and we wouldn't think that a cloned person was not a
person, just because she had the same genome as her genetic donor.
My view is that today's development underscores the logical problem
with treating blastocysts as if they have the same moral worth as a
person. If it seems implausible that we should treat every skin cell
as if it were a person, this is because the foundation of personhood
is not a human genome plus potential. There must be something more,
whether it be a neuronal structure, sentience, consciousness, the
ability to image a future, etc. But for the unconvinced -- and
especially those whose religious or ideological commitments make them
opposed to any research using blastocysts -- opposition to iPSC
research might be the only internally consistent position to take.
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