The Myth of "Therapeutic"
Cloning
Labeling human cloning for purposes of destructive experiments
as "therapeutic cloning" is a stroke of marketing genius by cloning
supporters. But it has little or no basis in fact.
The "therapeutic"
need for human cloning has always been highly speculative; it now seems more
doubtful than ever in light of recent advances in adult stem cell research and
other noncontroversial alternatives. In the stem cell research debate, as one
recent news report observes, "There is one thing everyone agrees on: Adult
stem cells are proving to be far more versatile than originally
thought."1 Adult stem cells have shown they can be "pluripotent" –
producing a wide array of different cells and tissues.2 They can
also be multiplied in culture to produce an ample supply of tissue for
transplantation.3 Best of all, using a patient's own cells solves
all problems of tissue rejection, the chief advantage cited until now for use
of cloning.4
In 1997 the National Bioethics Advisory
Commission reviewed the idea of cloning human embryos to create "customized
stem cell lines" but described this as "a rather expensive and far-fetched
scenario" – and added that a moral assessment is necessary as well:
Because of ethical and moral concerns raised by the use of
embryos for research purposes it would be far more desirable to explore the
direct use of human cells of adult origin to produce specialized cells or
tissues for transplantation into patients.5
Now PPL
Therapeutics, the Scottish firm involved in creating "Dolly" the sheep, says
it has indeed found a way to reprogram ordinary adult cells to become stem
cells capable of being directed to form almost any kind of cell or tissue –
without creating or destroying any embryos.6
Even in the
field of embryonic stem cell research, new developments have called into
question the need for cloning. The problem of tissue rejection may not be as
serious as once thought when cells from early human development are used, and
there are other ways of solving the problem – for example, by genetically
modifying cells to become a closer match to a patient.7
For
all these reasons, a recent overview of the field concludes that human
"therapeutic cloning" is "falling from favour," that "many experts do not now
expect therapeutic cloning to have a large clinical impact." Even James
Thomson of the University of Wisconsin, a leading practitioner and advocate of
embryonic stem cell research generally, calls this approach "astronomically
expensive"; in light of the enormous wastefulness of the cloning process and
the damage it does to gene expression, "many researchers have come to doubt
whether therapeutic cloning will ever be efficient enough to be commercially
viable" even if one could set aside the grave moral issues
involved.8
In short, the "therapeutic" case for human
cloning is as medically questionable as it is morally abhorrent.
Notes
- A. Zitner, "Diabetes Study Fuels Stem Cell Funding War," Los Angeles
Times, April 27, 2001
(www.latimes.com/news/nation/updates2/lat_stemwar010427.htm).
- Citing eleven other studies, a study funded by the National Institutes
of Health (NIH) and the Christopher Reeve Paralysis Foundation states:
"Pluripotent stem cells have been detected in multiple tissues in the adult,
participating in normal replacement and repair, while undergoing
self-renewal." D. Woodbury et al., "Adult Rat and Human Bone Marrow Stromal
Cells Differentiate Into Neurons," 61 Journal of Neuroscience
Research 364-370 (August 15, 2000) at 364.
- See: D. Colter et al., "Rapid expansion of recycling stem cells in
cultures of plastic-adherent cells from human bone marrow," 97 Proc.
Natl. Acad. Sci. USA 3213-8 (March 28, 2000)(adult stem cells amplified
a billion-fold in six weeks, retaining their multipotentiality for
differentiation); E. Rosler et al., "Cocultivation of umbilical cord blood
cells with endothelial cells leads to extensive amplification of competent
CD34+CD38- cells," 28 Exp. Hematol. 841-52 (July 2000).
- A recent report on use of adult stem cells to form new muscles, nerves,
liver cells and blood vessels observes: "None of these approaches use
embryonic stem cells, which some oppose on ethical grounds. Another
advantage is that they use tissue taken from the patient's own body, so
there is no risk of rejection or need for drugs to suppress immune system
defenses." See "Approach may renew worn hearts," Associated Press, November
12, 2000.
- Cloning Human Beings: Report and Recommendations of the National
Bioethics Advisory Commission (Rockville, MD: June 1997) at 30-31. The
Commission outlined three alternative avenues of stem cell research, two of
which seemed not to involve creating human embryos at all.
- "PPL follows Dolly with cell breakthrough," Financial Times,
February 23, 2001.
- P. Aldhous, "Can they rebuild us?", 410 Nature 622-5 (5 April
2001) at 623.
- Id. at
622.
__________________________
Secretariat for Pro-Life Activities
United States Conference of
Catholic Bishops
3211 4th Street, N.E., Washington, DC 20017-1194 (202)
541-3070
June 03, 2003 Copyright © by United
States Conference of Catholic Bishops