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Federal Document Clearing House
Congressional Testimony
January 24, 2002 Thursday
SECTION: CAPITOL HILL HEARING TESTIMONY
LENGTH: 986 words
COMMITTEE:
SENATE APPROPRIATIONS
SUBCOMMITTEE:
LABOR, HEALTH AND HUMAN SERVICES, EDUCATION
HEADLINE:
CLONING
TESTIMONY-BY: IRVING L. WEISSMAN, CHAIR, PANEL
ON SCIENTIFIC AND MEDICAL ASPECTS OF
AFFILIATION: HUMAN
REPRODUCTIVE CLONING
BODY: Statement of
Irving L. Weissman Chair, Panel on Scientific and Medical Aspects of
Human Reproductive Cloning
National Academy of Sciences National Academy
of Engineering Institute of Medicine National Research Council
And
Karel and Avice Beekhuis Professor of Cancer Biology, and Professor of
Pathology and Developmental Biology Stanford University, Stanford, Calif.
Concerning the Scientific and Medical Aspects of Human Reproductive
Cloning
Before the Subcommittee on Labor, Health and Human Services,
Education, and Related Agencies Committee on Appropriations U.S. Senate
January 24, 2002
Mr. Chairman and members of the Subcommittee.
My name is Irv Weissman. I am a professor at Stanford Medical School, and my
main research field for the last 20 years has been the biology and
transplantation of adult stem cells in mice and humans. I am here as chair of
the National Academies Panel on Scientific and Medical Aspects of
Human
Cloning, which released its report on January 18, 2002. The charge to
the panel in June 2001 was to examine the scientific and medical issues relevant
to human reproductive cloning, including the protection of human subjects, and
to clarify how human reproductive cloning differs from stem cell research. Our
charge did not extend to an examination of the ethical issues related to human
reproductive cloning.
We needed to determine whether current methods for
reproductive cloning are scientifically feasible and reproducible and are
medically safe. In addition, we needed to examine whether human participants in
the process could be adequately advised and protected. Society and its leaders
will need such scientific and medical information if they are to address the
relevant ethical and public-policy issues.
In reproductive cloning, the
nucleus of a body cell is transplanted into an egg whose nucleus had been
removed, stimulating it to divide to produce a blastocyst embryo; the blastocyst
is then placed into a uterus with the intent of creating a newborn.
In a
related but different procedure, cells are isolated from a blastocyst derived by
nuclear transplantation, and the cells are used to produce stem cell lines. This
is shown in the figure. Such stem cells are unspecialized cells that can develop
into almost all kinds of body cells. In what is sometimes called therapeutic
cloning, the donor of a nucleus for transplantation to produce stem cells can be
a person in whom stem cell daughter cells will be used to regenerate damaged
tissues. There is another medical use for nuclear transplantation to produce
stem cells; stem cells derived from a body cell or a disease cell of a patient
who had inherited the risk for that disease could be powerful tools for medical
research and lead to improved therapies.
We studied the scientific and
medical literature and held a workshop with world leaders in the relevant
technologies. Among the participants were persons who planned to clone human
beings. The data from animal studies of reproductive cloning demonstrate that
only a small percentage of the attempts are successful, that many of the
resulting clones die during all stages of gestation, that newborn clones often
are abnormal or die, and that the procedures carry serious risks for the mother.
However, the data on nuclear transplantation to produce stem cells show that
these cells are functional.
Given those findings, the panel unanimously
approved the following recommendations
Human reproductive cloning should
not now be practiced. It is dangerous and likely to fail. The panel therefore
unanimously supports the proposal that there should be a legally enforceable ban
on the practice of human reproductive cloning.
The scientific and
medical considerations related to this ban should be reviewed within five years.
The ban itself should be reconsidered only if at least two conditions are met:
(1) a new scientific and medical review indicates that the procedures are likely
to be safe and effective, and (2) a broad national dialogue on the societal,
religious, and ethical issues suggests that a reconsideration of the ban is
warranted.
Finally, the scientific and medical considerations that
justify a ban on human reproductive cloning at this time are not applicable to
nuclear transplantation to produce stem cells. Because of the considerable
potential for developing new medical therapies for life-threatening diseases and
advancing fundamental knowledge, the panel supports the conclusion of a recent
National Academies report that recommended that biomedical research using
nuclear transplantation to produce stem cells be permitted. A broad national
dialogue on the societal, religious, and ethical issues is encouraged on this
matter.
Scientists place high value on the freedom of inquiry--a freedom
that underlies all forms of scientific and medical research. Recommending
restriction of research is a serious matter, and the reasons for such a
restriction must be compelling. In the case of human reproductive cloning, we
are convinced that the potential dangers to the implanted fetus, to the newborn,
and to the woman carrying the fetus constitute just such compelling reasons. In
contrast, there are no scientific or medical reasons to ban nuclear
transplantation to produce stem cells, and such a ban would certainly close
avenues of promising scientific and medical research.
The panel stressed
that all concerned segments of society should examine and debate the broad
societal and ethical issues associated with human reproductive cloning, as well
as those associated with nuclear transplantation to produce stem cells. We hope
our report will help this Subcommittee and President Bush's Council on Bioethics
in this regard.
Thank you for the opportunity to testify. I hope that my
statement and the panel report can be put into the record. I will be happy to
answer questions.
LOAD-DATE: January 24, 2002