The risk of severe congenital defects would be prohibitively high in humans. Second, even if SCNT could be carried out safely in humans, some object that it violates human dignity and undermines traditional, fundamental moral, religious, and cultural values A cloned child would have only one genetic parent and would be the genetic twin of that parent.
For these reasons, cloning for reproductive purposes is widely considered morally wrong and is illegal in a number of states. Moreover, some people argue that because the technique of SCNT can be used for reproduction, its development and use for basic research should be banned.
Because of the shortage of human oocytes for SCNT research, some scientists wish to use nonhuman oocytes to derive lines using human nuclear DNA. Some opponents fear the creation of chimeras—mythical beasts that appear part human and part animal and have characteristics of both humans and animals Opponents may feel deep moral unease or repugnance, without articulating their concerns in more specific terms. Some people view such hybrid embryos as contrary to a moral order embodied in the natural world and in natural law.
In this view, each species has a particular moral purpose or goal, which mankind should not try to change. Others view such research as an inappropriate crossing of species barriers, which should be an immutable part of natural design. Finally, some are concerned that there may be attempts to implant these embryos for reproductive purposes.
In rebuttal, supporters of such research point out that the biological definitions of species are not natural and immutable but empirical and pragmatic 40 , 41 , Animal-animal hybrids of various sorts, such as the mule, exist and are not considered morally objectionable.
Moreover, in medical research, human cells are commonly injected into nonhuman animals and incorporated into their functioning tissue.
Indeed, this is widely done in research with all types of stem cells to demonstrate that cells are pluripotent or have differentiated into the desired type of cell. In addition, some concerns can be addressed through strict oversight 40 , for example prohibiting reproductive uses of these embryos and limiting in vitro development to 14 d or the development of the primitive streak, limits that are widely accepted for other hESC research. Finally, some people regard repugnance per se an unconvincing guide to ethical judgments.
People disagree over what is repugnant, and their views might change over time. Blood transfusion and cadaveric organ transplantation were originally viewed as repugnant but are now widely accepted practices.
Furthermore, after public discussion and education, many people overcome their initial concerns. Pluripotent stem cells can be derived from fetal tissue after abortion. However, use of fetal tissue is ethically controversial because it is associated with abortion, which many people object to.
Under federal regulations, research with fetal tissue is permitted provided that the donation of tissue for research is considered only after the decision to terminate pregnancy has been made. Somatic cells can be reprogrammed to form pluripotent stem cells 45 , 46 , called induced pluripotential stem cells iPS cells.
These iPS cell lines will have DNA matching that of the somatic cell donors and will be useful as disease models and potentially for allogenic transplantation. Early iPS cell lines were derived by inserting genes encoding for transcription factors, using retroviral vectors. Researchers have been trying to eliminate safety concerns about inserting oncogenes and insertional mutagenesis.
Reprogramming has been successfully accomplished without known oncogenes and using adenovirus vectors rather than retrovirus vectors.
A further step was the recent demonstration that human embryonic fibroblasts can be reprogrammed to a pluripotent state using a plasmid with a peptide-linked reprogramming cassette 47 , Not only was reprogramming accomplished without using a virus, but the transgene can be removed after reprogramming is accomplished.
The ultimate goal is to induce pluripotentiality without genetic manipulation. Because of unresolved problems with iPS cells, which currently preclude their use for cell-based therapies, most scientists urge continued research with hESC Furthermore, because a skin biopsy to obtain somatic cells is relatively noninvasive, there are fewer concerns about risks to donors compared with oocyte donation. Neither the donation of materials to derive iPS cells nor their derivation raises special ethical issues.
Some potential downstream uses of iPS cell derivatives may be so sensitive as to call into question whether the original somatic cell donors would have agreed to such uses These standard research techniques are widely used in other types of basic research, including research with stem cells from other sources.
Generally, donors of biological materials are not explicitly informed of these research procedures, although such disclosure is now proposed for whole genome sequencing 52 , Such studies are of fundamental importance in stem cell biology, for example to characterize the lines and to demonstrate that they are pluripotent. Large-scale genome sequencing will yield insights about the pathogenesis of disease and identify new targets for therapy.
However, some downstream research could also raise ethical concerns. For example, large-scale genome sequencing may evoke concerns about privacy and confidentiality. Donors might consider it a violation of privacy if scientists know their future susceptibility to many genetic diseases. Furthermore, it may be possible to reidentify the donor of a deidentified large-scale genome sequence using information in forensic DNA databases or at an Internet company offering personal genomic testing 54 , Other donors may object to their cells being injected into animals.
For example, they may oppose all animal research, or they may have religious objections to the mixing of human and animal species.
The injection of human neural progenitor cells into nonhuman animals has raised ethical concerns about animals developing characteristics considered uniquely human 56 , Still other donors may not want cell lines derived from their biological materials to be patented as a step toward developing new tests and therapies. People are unlikely to drop such objections even if the cell lines were deidentified or even if many years had passed since the original donation. Thus there may be a tension between respecting the autonomy of donors and obtaining scientific benefit from research, which can be resolved during the process of obtaining consent for the original donation of materials.
It would be unfortunate if iPS cell lines that turned out to be extremely useful scientifically for example because of robust growth in tissue culture could not be used in additional research because the somatic cell donor objected. One approach to avoid this is to preferentially use somatic cells from donors who are willing to allow all such basic stem cell research and to be contacted for future sensitive research that cannot be anticipated at the time of consent Donors could also be offered the option of consenting to additional specific types of sensitive but not fundamental downstream research, such as allogenic transplantation into other humans and reproductive research involving the creation of totipotent entities.
Because these concerns about consent for sensitive downstream research also apply to other types of stem cells, it would be prudent to put in place similar standards for consent to donate materials for derivation of other types of stem cells. However, these concerns are particularly salient for iPS cells because of the widespread perception that these cells raise no serious ethical problems and because they are likely to play an increasing role in stem cell research.
Transplantation of cells derived from pluripotent stem cells offers the promise of effective new treatments. However, such transplantation also involves great uncertainty and the possibility of serious risks. Some stem cell therapies have been shown to be effective and safe, for example hematopoietic stem cell transplants for leukemia and epithelial stem cell-based treatments for burns and corneal disorders Although supporting medical innovation under very limited circumstances, the International Society for Stem Cell Research has decried such use of unproven hSC transplantation.
These clinical trials should follow ethical principles that guide all clinical research, including appropriate balance of risks and benefits and informed, voluntary consent. Additional ethical requirements are also warranted to strengthen trial design, coordinate scientific and ethics review, verify that participants understand key features of the trial, and ensure publication of negative findings These measures are appropriate because of the highly innovative nature of the intervention, limited experience in humans, and the high hopes of patients who have no effective treatments.
Evidence of safety and proof of principle should be established through appropriate preclinical studies in relevant animal models or through human studies of similar cell-based interventions. Requirements for proof of principle and safety should be higher if cells have been manipulated extensively in vitro or have been derived from pluripotent stem cells Even with these safeguards, however, because of the highly innovative nature of the intervention and limited experience in humans, unanticipated serious adverse events may occur.
Although the transplanted cells localized to the target areas of the brain, engrafted, and functioned to produce the intended neurotransmitters, appropriately regulated physiological function was not achieved. Participants in phase I trials may not thoroughly understand the possibility that hESC transplantation might make their condition worse. Problems with informed consent are well documented in phase I clinical trials. Participants in cancer clinical trials commonly expect that they will benefit personally from the trial, although the primary purpose of phase I trials is to test safety rather than efficacy Analyses of cancer clinical trials reveal that the information in consent forms generally is adequate.
Participants in phase I stem cell-based clinical trials might overestimate their benefits and underestimate the risks. The scientific rationale for hSC transplantation and preclinical results may seem compelling.
In addition, highly optimistic press coverage might reinforce unrealistic hopes. Several measures may enhance informed consent in early stem cell-based clinical trials First, researchers should describe the risks and prospective benefits in a realistic manner.
Researchers need to communicate the distinction between the long-term hope for effective treatments and the uncertainty inherent in any phase I trial. Participants in phase I studies need to understand that the intervention has never been tried before in humans for the specific condition, that researchers do not know whether it will work as hoped, and that the great majority of participants in phase I studies do not receive a direct benefit.
Second, investigators in hESC clinical trials should discuss a broader range of information with potential participants than in other clinical trials. The doctrine of informed consent requires researchers to discuss with potential participants information that is pertinent to their decision to volunteer for the clinical trial Generally, the relevant information concerns the nature of the intervention being studied and the risks and prospective benefits.
However, in hESC transplantation, nonmedical issues may be prominent or even decisive for some participants. Individuals who regard the embryo as having the moral status of a person would likely have strong objections to receiving hESC transplants. Although this intervention might benefit them medically, such individuals might regard it as complicit with an immoral action.
Thus researchers in clinical trials of hESC transplantation should inform eligible participants that transplanted materials originated from human embryos. Third, and most important, researchers should verify that participants have a realistic understanding of the clinical trial The crucial ethical issue about informed consent is not what researchers disclose in consent forms or discussions, but rather what the participants in clinical trials understand.
In other contexts, some researchers have ensured that participants understand the key features of the trial by assessing their comprehension. In HIV clinical trials in developing countries, where it has been alleged that participants did not understand the trial, many researchers are now testing each participant to be sure he or she understands the essential features of the research We urge that such tests of comprehension be carried out in phase I trials of hSC transplantation 58 , Careful attention to consent in highly innovative clinical trials might prevent controversies later.
In early clinical trials of organ transplantation, the implantable totally artificial heart, and gene transfer, the occurrence of serious adverse events led to allegations that study participants had not truly understood the nature of the research 66 , 67 , The resulting ethical controversies brought about negative publicity and delays in subsequent clinical trials. Human stem cell research raises some ethical issues that are beyond the mission of institutional review boards IRBs to protect human subjects, as well as the expertise of IRB members.
There should be a sound scientific justification for using human oocytes and embryos to derive new human stem cell lines. However, IRBs usually do not carry out in-depth scientific review. An institutional SCRO with appropriate scientific and ethical expertise, as well as public members, should be convened at each institution to review, approve, and oversee stem cell research 18 , 69 , Because of the sensitive nature of hSC research, the SCRO should include nonaffiliated and lay members who can ensure that public concerns are taken into account.
Sharing stem cells across institutions facilitates scientific progress and minimizes the number of oocytes, embryos, and somatic cells used. However, ethical concerns arise if researchers work with lines that were derived in other jurisdictions under conditions that would not be permitted at their home institution. Researchers and SCROs need to distinguish core ethical standards that are accepted by international consensus—informed consent and an acceptable balance of benefits and risks—from standards that vary across jurisdictions and cultures.
Using lines whose derivation violated core standards would erode ethical conduct of research by providing incentives to others to violate those standards.
The review process should focus on those types of hSC derivation that raise heightened levels of ethical concern Dilemmas occur when donors of research oocytes receive payments in excess of their expenses and such payments are not permitted in the jurisdiction where the hSC cells will be used.
For example, the United Kingdom enacted an explicit policy to allow such payment after public consultation and debate and provided reasons to justify its decision 72 , 73 , 74 , Jurisdictions that ban payments should accept such carefully considered policies as a reasonable difference of opinion on a complex issue. Concerns about payment should be less if lines were derived from frozen embryos remaining after IVF treatment and donors were paid in the reproductive context.
Such payments, which were carried out before donation for research was actually considered, are not an inducement for hESC research Other dilemmas arise with hESC lines derived from embryos using gamete donors. As previously discussed, explicit consent for the use of reproductive materials in stem cell research should be obtained from any gamete donors as well as embryo donors 13 , Use of such older lines is appropriate because it would be unreasonable to expect physicians to comply with standards that had not yet been developed It would also be acceptable to grandparent lines if gamete donors agreed to unspecified future research or gave dispositional control of frozen embryos to the woman or couple in IVF.
However, the derivation should be consistent with the ethical and legal standards in place at the time the line was derived. In summary, hSC research offers exciting opportunities for scientific advances and new therapies, but also raises some complex ethical and policy issues.
These issues need to be discussed along with scientific challenges to ensure that stem cell research is carried out in an ethically appropriate manner. The authors have no conflicts of interest to declare. First Published Online April 14, National Center for Biotechnology Information , U. Published online Apr Bernard Lo and Lindsay Parham. Address all correspondence and requests for reprints to: Received Jul 10; Accepted Mar This article has been cited by other articles in PMC.
Multipotent Stem Cells A. Cord blood stem cells. Embryonic Stem Cell Research A. Existing embryonic stem cell lines. Ethical concerns about SCNT. Stem Cell Clinical Trials A. Risks and prospective benefits in stem cell clinical trials. Table 1 Ethical issues at different phases of stem cell research. Phase of research Ethical issues Donation of biological materials Informed and voluntary consent Research with hESCs Destruction of embryos Creation of embryos specifically for research purposes 1.
Payment to oocyte donors 2. Medical risks of oocyte retrieval 3. Protecting reproductive interests of women in infertility treatment Use of stem cell lines derived at another institution Conflicting legal and ethical standards Stem cell clinical trials Risks and benefits of experimental intervention Informed consent.
Open in a separate window. Multipotent Stem Cells Adult stem cells and cord blood stem cells do not raise special ethical concerns and are widely used in research and clinical care. Cord blood stem cells Hematopoietic stem cells from cord blood can be banked and are widely used for allogenic and autologous stem cell transplantation in pediatric hematological diseases as an alternative to bone marrow transplantation.
Adult blood stem cells Adult stem cells occur in many tissues and can differentiate into specialized cells in their tissue of origin and also transdifferentiate into specialized cells characteristic of other tissues. Embryonic Stem Cell Research Pluripotent stem cell lines can be derived from the inner cell mass of the 5- to 7-d-old blastocyst.
Existing embryonic stem cell lines In , President Bush, who holds strong pro-life views, allowed federal National Institutes of Health NIH funding for stem cell research using embryonic stem cell lines already in existence at the time, while prohibiting NIH funding for the derivation or use of additional embryonic stem cell lines.
New embryonic stem cell lines from frozen embryos Women and couples who undergo infertility treatment often have frozen embryos remaining after they complete their infertility treatment. Informed consent for donation of materials for stem cell research. Consent from gamete donors. Confidentiality of donor information. Ethical concerns about oocyte donation for research Concerns about oocyte donation specifically for research are particularly serious in the wake of the Hwang scandal in South Korea, in which widely hailed claims of deriving human SCNT lines were fabricated.
Medical risks of oocyte retrieval. Protecting the reproductive interests of women in infertility treatment. Payment to oocyte donors. Informed consent for oocyte donation. Ethical concerns about SCNT 1. Objections to creating embryos specifically for research. Objections to human reproduction using SCNT. Fetal Stem Cells Pluripotent stem cells can be derived from fetal tissue after abortion. Downstream research Some potential downstream uses of iPS cell derivatives may be so sensitive as to call into question whether the original somatic cell donors would have agreed to such uses Genetic modifications of cells.
Injection of derived cells into nonhuman animals to demonstrate their function, including the injection into the brains of nonhuman animals. Patenting scientific discoveries and developing commercial tests and therapies, with no sharing of royalties with donors Stem Cell Clinical Trials Transplantation of cells derived from pluripotent stem cells offers the promise of effective new treatments.
Informed consent in early stem cell clinical trials Problems with informed consent are well documented in phase I clinical trials. Institutional Oversight of Stem Cell Research Human stem cell research raises some ethical issues that are beyond the mission of institutional review boards IRBs to protect human subjects, as well as the expertise of IRB members. The stem cell research oversight committee SCRO An institutional SCRO with appropriate scientific and ethical expertise, as well as public members, should be convened at each institution to review, approve, and oversee stem cell research 18 , 69 , Use of stem cell lines derived at another institution Sharing stem cells across institutions facilitates scientific progress and minimizes the number of oocytes, embryos, and somatic cells used.
First Published Online April 14, Abbreviations: National Institutes of Health July 17, Statement of Senator Orrin G. Hatch on stem cell research. Accessed December 18, Streiffer R Informed consent and federal funding for stem cell research. Hastings Cent Rep Willingness to donate frozen embryos for stem cell research. Harvard University Press Assisted reproductive technologies.
National Bioethics Advisory Commission Kalfoglou AL, Geller G A follow-up study with oocyte donors exploring their experiences, knowledge, and attitudes about the use of their oocytes and the outcome of the donation. Investigations document still more problems for stem cell researchers. How young Korean researchers helped unearth a scandal.
National Academies Press Ethical and policy issues in research involving human participants. N Engl J Med S28 Hyun I Fair payment or undue inducement? Kennedy Inst Ethics J Embryonic Stem Cells are developed from a female egg after it is fertilized by sperm. The process takes days. Stem cell research is used for investigation of basic cells which develop organisms.
The cells are grown in laboratories where tests are carried out to investigate fundamental properties of the cells. The controversy surrounding stem cell research led to an intense debate about ethics.
Up until the recent years, the research method mainly focused on Embryonic Stem Cells, which involves taking tissue from an aborted embryo to get proper material to study. This is typically done just days after conception or between the 5th and 9th week. This is probably an important advancement in stem cell research, since it allows researchers to obtain pluripotent stem cells, which are important in research, without the controversial use of embryos.
There were two main issues concerning stem cell research with both pros and cons:. The first issue is really not just about stem cell research, as it may be applied to most research about human health. Since , the second point, concerns about the methods involved, has been less debated, because of scientific developments such as iPS. As you will most probably notice, the following arguments are not exclusively in use when talking about stem cell research.
Stem cell research can potentially help treat a range of medical problems. It could lead humanity closer to better treatment and possibly cure a number of diseases:. Better treatment of these diseases could also give significant social benefits for individuals and economic gains for society.
The controversy regarding the method involved was much tenser when researchers used Embryonic Stem Cells as their main method for stem cell research. These points are based on the old debate about the methods of stem cells research, from before Since then, scientists have moved on to use more ethical methods for stem cell research, such as iPS.
This section serves as an illustration of the difficult evaluations researchers may have to analyze. The stem cell-research is an example of the, sometimes difficult, cost-benefit analysis in ethics which scientists need to do. Even though many issues regarding the ethics of stem cell research have now been solved, it serves as a valuable example of ethical cost-benefit analysis.
The previously heated debate seems to have lead to new solutions which makes both sides happier. Stem Cell pros and cons had to be valued carefully, for a number of reasons.
When you are planning a research project, ethics must always be considered. If you cannot defend a study ethically, you should not and will not be allowed to conduct it. You cannot defend a study ethically unless the presumed cost is lower than expected benefits. Why was the debate regarding the stem cell research so intense? First, it was a matter of life - something impossible to measure. And in this case, researchers had to do exactly that: Both an abortion and someone dying, suffering from a possible curable disease, is a tragedy.
Which have the highest value? Does a big breakthrough in the research justify the use of the method in the present? Would the benefits of studying abortions outweigh the costs? The choice was subjective: Nobody knows all the risks or all the possible outcomes, so we had to value it with our perception of the outcome. Perception is influenced by our individual feelings, morals and knowledge about the issue.
Second, at the time we did not know whether the research was necessary and sufficient to give us the mentioned health benefits.
Stem Cells: Looking Towards the Future. This may seem like a unreligious view, but Stem Cell research is neccesary for our future. Just think of all the people who are suffering, and how we could lessen that pain.
Watch video · But embryonic stem cell research could lead to the discovery of new medical treatments that would alleviate the suffering of many people. So which moral principle should have the upper hand in this situation?
Examining the ethics of embryonic stem cell research Following the recent passage by both houses of Congress of the Stem Cell Research Enhancement Act of , which would permit federal funding of research using donated surplus embryonic stem cells from fertility clinics, the president has once again threatened a veto. The controversy surrounding stem cell research led to an intense debate about ethics. Up until the recent years, the research method mainly focused on Embryonic Stem Cells, which involves taking tissue from an aborted embryo to get proper material to study. This is typically done just days after conception or between the 5th and 9th week.
Stem cell research should be allowed. Research involving stem cells derived from human embryos should be permitted in Ireland in certain circumstances, a new report is to recommend. Stem cells are basic cells that can multiply and generate into specialised cells, tissues and even organs. 1 Should Research on Stem Cells Be Allowed? Peter Schaber (University of Zurich) Research with stem cells promises new therapies for injuries and diseases.