www.sciencemag.org SCIENCEVOL 315
2 FEBRUARY 2007
COURTESY OF M. WILLIAM LENSCH, CHILDREN’S HOSPITAL BOSTON
gious perspectives are potential barriers to
international collaboration in this fledgling
field. Recognizing the need for scientists to
act transparently, to serve the public interest,
and to preserve public trust, the International
Society for Stem Cell Research (ISSCR) con-
vened a task force to formulate guidelines for
human ES cell research. The ISSCR guide-
lines were written by scientists, ethicists, and
legal experts from 14 countries (1).
The ISSCR guidelines encompass the
core values put forth by the Committee on
Guidelines for Human ES Cell Research of the
U.S. National Academy of Sciences (U.S.
NAS) (2) and the Regulations of the California
Institute for Regenerative Medicine (3), and
acknowledge thoughtful governmental regula-
tions already in place in several countries,
particularly that of the Human Fertilisation
and Embryology Authority of the United
Kingdom (4). The ISSCR is the principal
scientific society for stem cell scientists and
transcends institutional, regional, and national
uman embryonic stem (ES) cells are
valuable for biomedicine, but differ-
ing cultural, political, legal, and reli-
The ISSCR guidelines focus on research
pertinent to derivation and use of pluripotent
human stem cell lines and are not meant to
encompass somatic (adult) stem cell research
or human embryo or fetal tissue research. The
ISSCR guidelines aim to facilitate interna-
tional collaboration by encouraging investiga-
tors and institutions to adhere to a uniform set
of practices. The ISSCR guidelines are sub-
servient to all applicable laws and regulations
of the country or region where the actual
research takes place.
Call for oversight. Biomedical research is
already subject to regulation and oversight.
However, because human ES cell research
raises unique and sensitive issues and requires
specialized expertise to judge both scientific
merit and ethical propriety, the ISSCR guide-
lines call for a specialized oversight process to
complement existing institutional review
boards. In contrast to the U.S. NAS guidelines,
which stipulated that institutions engaged in
human ES cell research should form an
ES cell research oversight (ESCRO) com-
mittee, the ISSCR guidelines do not specify
the precise form of stem cell research over-
sight (SCRO). The ISSCR guidelines specify
the key elements of a single rigorous review
at the institutional, regional, national, or inter-
national level, thereby eliminating redun-
dancy and allowing flexibility for varied
oversight mechanisms in different countries.
Permissible and impermissible research.
The ISSCR guidelines prohibit (i) all experi-
ments that lack a compelling scientific ratio-
nale or raise strong shared ethical concerns—
in particular human reproductive cloning; (ii)
in vitro culture of human embryos beyond 14
days or the formation of the primitive embry-
onic streak; and (iii) the interbreeding of ani-
mals likely to harbor human gametes.
The “14-day limit,” first articulated in
1984 by the Warnock committee of the
U. K. Human Fertilisation and Embryology
Authority (5), is widely accepted by re-
searchers in the human stem cell and fertility
fields. It recognizes the significant biological
distinctions between the earliest human embryos,
The International Society for Stem Cell
Research describes major principles that
should guide ethical stem cell research.
The ISSCR Guidelines for Human
Embryonic Stem Cell Research
How can ethical principles for research encompass cultural differences? Shown is a human embryonic
stem cell colony, on a background of mouse embryonic fibroblast feeder cells, stained with Wright-Giemsa to
highlight the individual cells of the colony.
1Children’s Hospital Boston. 2Karolinska Institutet.
3GlobalStem, Inc. 4The Hebrew University. 5University of
Wisconsin Law School. 6Bird & Bird, Beijing, China.
7Peking University. 8Howard Hughes Medical Institute,
University of California, San Diego School of Medicine.
9Berman Bioethics Institute, Johns Hopkins University.
10Case Western Reserve University School of Medicine.
11Institute of Global Management, Seoul, Korea. 12Wilmer
Cutler Pickering Hale and Dorr LLP. 13National University
of Singapore. 14Cambridge University. 15University of
Utrecht Medical School. 16Kyoto University. 17Brigham
and Women’s Hospital, Harvard Medical School.
18International Society for Stem Cell Research. 19University
of Toronto. 20Max Planck Institute for Molecular Bio-
medicine. 21University of Oslo and University of Bergen.
22Monash University. 23Stanford University School of
Medicine. 24University of Edinburgh. 25Genomics Research
Center, Academia Sinica, Taiwan. 26Feinberg School
of Medicine, Northwestern University. [For complete
addresses, see SOM.]
*Author for correspondence. E-mail: george.daley@
George Q. Daley,1* Lars Ahrlund-Richter,2Jonathan M. Auerbach,3Nissim Benvenisty,4R. Alta
Charo,5Grace Chen,6Hong-kui Deng,7Lawrence S. Goldstein,8Kathy L. Hudson,9Insoo Hyun,10
Sung Chull Junn,11Jane Love,12Eng Hin Lee,13Anne McLaren,14Christine L. Mummery,15Norio
Nakatsuji,16Catherine Racowsky,17Heather Rooke,1,18Janet Rossant,19Hans R. Schöler,20Jan
Helge Solbakk,21Patrick Taylor,1Alan O. Trounson,22Irving L. Weissman,23Ian Wilmut,24John Yu,25
Published by AAAS
on September 25, 2009
2 FEBRUARY 2007VOL 315 SCIENCE www.sciencemag.org Download full-text
which have not yet established even the most
rudimentary rostral and caudal orientation
(the primitive streak), and an embryo that has
begun to initiate organogenesis. The U.S. NAS
guidelines prohibit the mixing of cells of
any nature with the pre-streak embryo. This
restriction excludes a number of experiments
considered standard in animal embryology,
including cell aggregation studies to investi-
gate the segregation of primitive embryonic
blastomeres into inner cell mass and trophec-
toderm. Such experiments might yield in-
sights into the origins of stem cells and might
enhance the efficiency of ES cell derivation.
The ISSCR Task Force reasoned that experi-
ments with sound scientific rationale that
respect the 14-day limit are permissible if they
pass a thorough SCRO review.
The ISSCR guidelines diverge subtly from
the U.S. NAS guidelines in restrictions placed
on breeding of animals that might carry
human gametes. Such experiments might be
justified to investigate the consequences of
tissue repair or regeneration on reproductive
behavior or function, and they could be done
with safeguards to prevent any inadvertent
fertilization events (e.g., sterilization). The
ISSCR guidelines place the onus on the
SCRO process to evaluate permissibility of
any particular experiment.
Experiments that are permissible only
after SCRO review and approval include deri-
vation of new lines or creation of animal
chimeras, especially experiments likely to
result in extensive chimerism of the brain or
germ line. The ISSCR guidelines provide a
means for excluding in vitroexperiments with
existing human ES cell lines from review, as
appropriate, and exclude from SCRO review
routine procedures that raise no appreciable
moral concerns, such as assays of teratoma
formation from human ES cell lines. Under
the U.S. NAS guidelines, the teratoma assay
requires ESCRO committee review because
it entails the creation of a chimeric animal.
We anticipate that other procedures may
become exempt from SCRO review as the
Requirement for explicit consent. For use
of somatic cell nuclei in nuclear transfer
experiments, the ISSCR guidelines call for
obtaining contemporaneous and explicit con-
sent from all somatic cell donors. Such a rigid
requirement reinforces a position stated by the
U.S. NAS guidelines to protect individuals
who might not want their tissues unwittingly
used in human ES cell research. For the re-
search use of embryos generated with donated
gametes, the ISSCR guidelines reaffirm the
need for explicit consent from both gamete
donors. In the future, informed consent for all
gamete donors should include the possible use
of donated materials and their derivatives in
human stem cell research.
Financial considerations. In some nations,
like the United States, women who provide
their eggs to infertile couples are routinely
compensated—that is, provided money
in addition to reimbursement of direct ex-
penses—in a range that varies widely but is
typically from $2500 to $5000 (6). Some
believe that high payments may unduly induce
women to ignore the risks of hormonal stimu-
lation and surgical egg retrieval and thus may
undermine the voluntary nature of women’s
choices to provide their eggs to infertile cou-
ples. Task force members had varied opinions
on what financial accommodations should be
allowed for donation of oocytes for research
purposes. Some felt that altruism should be
the only permissible motivation for research
donation; others felt that asking women to
bear the significant burden of time, effort, dis-
comfort, and risk of donation without com-
pensation was itself unfair and exploitative.
There was consensus for providing reim-
bursement of direct expenses incurred during
the process of providing oocytes, although
there was concern that even this financial con-
sideration might invite abuse. The Task Force
noted that healthy research volunteers who
undergo invasive research procedures like
bone marrow biopsy or colonoscopy are
sometimes compensated, but could not reach
consensus on the permissibility of even a
modest honorarium for providing oocytes.
The Task Force concluded that research and
ethical review committees are experienced in
evaluating financial considerations and that
substantial literature documents their ability
to distinguish undue inducements from pay-
ments that appropriately acknowledge the
interests of the subject (7–10). Thus, the Task
Force agreed to allow the SCRO process
to determine the financial considerations
involved in egg procurement, guided by the
principle that “there must be a detailed and
rigorous review to ensure that reimburse-
ment of direct expenses or financial consid-
erations of any kind do not constitute an
Encouraging compliance. To encourage
adoption of the ISSCR guidelines by the
research community, and as a mechanism of
enforcement, the guidelines call for journal
editors and granting agencies, as a stipulation
for publication or funding, to require investi-
gators to attest to compliance with the ISSCR
guidelines or an equivalent set of regulations.
To set the guidelines into practice, sample
informed-consent documents for the procure-
ment of human research materials were cre-
ated and subjected to extensive peer review by
an external international group of ethicists,
research policy experts, and leaders of institu-
tional review boards and ES cell research
oversight committees. These documents en-
compass the principles articulated in the
ISSCR guidelines and are available from the
ISSCR Web site (11). The ISSCR hopes to
establish a database of human ES cell lines
that have been derived in accordance with the
Finally, the ISSCR guidelines state that
researchers engaging in human ES cell re-
search must make their materials readily acces-
sible to the biomedical research community.
The guidelines thus include recommendations
for the derivation, banking, storage, and distri-
bution of research materials, and provide a
sample Material Transfer Agreement to facili-
tate exchange of research materials (11).
The ISSCR leadership is committed to ongo-
ing review and revision of the guidelines, and
appreciates that new research in science,
ethics, law, and policy will challenge us with
new questions. We are hopeful that the many
communities affected by and attentive to stem
cell research will consider these guidelines a
call for their robust participation in the
processes that decide the direction of research.
The ISSCR seeks the support of its member-
ship, members of other scientific societies,
our institutions, and the public to promote
adoption of the ISSCR guidelines globally.
References and Notes
1. Ad hoc contributors: Richard Hynes, Howard Hughes
Medical Institute, Department of Biology, Massachusetts
Institute of Technology, Cambridge, MA; M. William
Lensch, Children’s Hospital, Boston, MA; Leonard I. Zon,
Howard Hughes Medical Institute, Children’s Hospital,
2. U.S. National Academy of Sciences, guidelines;
3. California Institute for Regenerative Medicine,
4. U.K. Human Fertilisation and Embryology Authority,
5. U.K. Committee on Human Fertilisation and Embryology,
Human Fertilisation and Embryology, M. Warnock, Chair;
available at www.bopcris.ac.uk/bopall/ref21165.html.
6. Ethics Committee of the American Society for
Reproductive Medicine, Fertil. Steril. 74, 216 (2000).
7. J. P. Bentley, P. G. Thacker, J. Med. Ethics 30, 293 (2004).
8. C. Grady, J. Clin. Invest. 115, 1681 (2005).
9. S. D. Halpern, J. H. Karlawish, D. Casarett, J. A. Berlin,
D. A. Asch, Arch. Intern. Med. 164, 801 (2004).
10. D. Wendler, J. E. Rackoff, E. J. Emanuel, C. Grady,
J. Pediatr. 141, 166 (2002).
11. ISSCR guidelines, www.isscr.org/guidelines/index.htm.
12. See SOM for conflict-of-interest statements.
Supporting Online Material
Published by AAAS
on September 25, 2009