Human-Animal Combinations in Stem Cell Research

22 SEP 2010

Release of a report by the Bioethics Advisory Committee

  1. The Bioethics Advisory Committee (BAC) announces the release of a report entitled “Human-Animal Combinations in Stem Cell Research”. The term “human-animal combinations” refers to any kind of living organism in which there is some mixing of human and animal materials. The Report focuses on two types of human-animal combinations: cytoplasmic hybrids and animal chimeras.

  2. A cytoplasmic hybrid is created by injecting the nucleus (genetic material) of a somatic cell from a human body into an enucleated animal egg. This technique, called somatic cell nuclear transfer (SCNT), allows disease-specific or patient-specific stem cells to be derived in order to study nuclear reprogramming and to understand genetic diseases.

  3. Animal chimeras are produced by injecting human stem cells into animals at various stages of development. Such chimeras are needed in research to study stem cell biology, as well as to find new and more effective ways to treat diseases.

  4. In view of increasing ethical debate on research involving human-animal combinations internationally, a working group was formed by the BAC in 2006 to consider the ethical, legal and social issues that may arise should researchers seek to conduct such research in Singapore. This initiative is also part of the BAC’s effort to update its recommendations for human stem cell research, especially in the light of recent developments. The BAC expects stem cell research to have considerable potential in the treatment of currently incurable diseases, such as spinal cord injury, diabetes, Alzheimer’s disease and Parkinson’s disease. Clinical trials of stem cell treatments are beginning in a number of countries

  5. The scientific rationale behind the creation of such human-animal combinations was examined by the working group, together with the ethical issues and regulatory policies in major scientific jurisdictions. A public consultation was conducted by the BAC from 8 January 2008 to 10 March 2008 to ascertain and understand the concerns of the Singaporean public. To facilitate public deliberation and discussion, a consultation paper was sent to 71 research, governmental and healthcare institutions, and professional and religious organisations for comment. In addition, members of the public were encouraged to share their views through various means including email, and an online discussion forum and e-consultation managed by REACH. Two public fora were held on 19 January 2008 and 16 August 2008. Separate meetings have also been held with representatives of regulatory bodies, members of institutional review boards, leaders of religious groups and stem cell researchers.

  6. After extensive consultation, deliberation and discussion, the BAC concludes that research involving human-animal combinations should be allowed on grounds of scientific merit, provided that a regulatory framework is in place, and ethical requirements or limits are properly observed. Five recommendations that are consistent with current international practices and guidelines are proposed in this Report to ensure that there is adequate and proper oversight, and to allay public concerns. The Report further considers the ethical, legal and social issues arising from the use of human-animal combinations in stem cell research, and reviews best practices that have been adopted in major scientific jurisdictions. It also attempts to dispel some misconceptions and addresses concerns about the research as revealed in the consultations.

  7. Professor Lim Pin, Chairman of the BAC, says: “Many people are concerned with the possibility of developing actual independent living creatures with both human and animal features, or animals with human consciousness or mental characteristics. Such a creature will not arise from research involving cytoplasmic hybrids as researchers should not be allowed to develop such hybrids beyond 14 days or the emergence of the primitive streak, whichever is earlier. As for chimeras created with human embryonic stem cells or any kind of pluripotent stem cells, they should not be allowed to breed.”

  8. Senior District Judge (ret.) Mr Richard Magnus, Chairman of the Human Embryo and Chimera Working Group, adds: “Ethics review will ensure that research involving human-animal combinations is permitted only where there is strong scientific merit, potential medical benefit and in the absence of a satisfactory alternative way of pursuing the same research. In addition, those who have a conscientious objection to such research should not be under a duty to conduct or assist in the research.”

  9. Currently, the Ministry of Health regulates certain types of research in Singapore, such as clinical research and research using human embryos. However, with research increasingly being done by research institutions that do not fall directly under the supervision of the Ministry, the BAC proposes that all human stem cell research, including research with human-animal combinations, be the responsibility of a national stem cell ethics review body. This body, which should include lay members of the public, could appropriately be under the jurisdiction of the Ministry.

List of Recommendations

Recommendation 1

A single national body, which must include lay members of the public, should be established to review and monitor all stem cell research involving human pluripotent stem cells or human-animal combinations conducted in Singapore. This body should also be empowered to determine the kinds of research that need not undergo its review.

Recommendation 2

The creation of cytoplasmic hybrid embryos should be permitted only where there is strong scientific merit in, and potential medical benefit from, such research. These embryos should not be allowed to develop beyond 14 days or the appearance of the primitive streak, whichever is earlier, nor be implanted into any human or animal uterus.

Recommendation 3

Where human embryonic stem cells, induced pluripotent stem cells, or any other kind of pluripotent stem cells are introduced into non-human animals at any stage of development, particular attention should be paid to the need to avoid the creation of entities in which human sentience or consciousness might be expected to occur.

Recommendation 4

Animals into which human embryonic stem cells, induced pluripotent stem cells, or any other kind of pluripotent stem cells have been introduced should not be allowed to breed.

Recommendation 5

No clinical or research personnel should be under a duty to conduct or assist in stem cell research involving human-animal combinations, to which they have a conscientious objection.

About the BAC

The BAC was established by the Government in December 2000 to address the ethical, legal and social issues arising from human biomedical research and its applications. It develops and recommends policies on these issues, with the aim of protecting the rights and welfare of individuals, while allowing the biomedical sciences to develop and realise its full potential for the benefit of mankind.

For media enquiries, please contact:


Mr Calvin Ho
DID: (65) 6773 6719
calvin_ho@bioethics-singapore.org