However, human stem cell (hSC) research also raises sharp ethical and political controversies. The derivation of pluripotent stem cell lines from oocytes and embryos is fraught with disputes regarding the onset of human personhood and human reproduction. Several other methods of deriving stem cells raise fewer ethical concerns. The reprogramming of somatic cells to produce induced pluripotent stem cells (iPS cells) avoids the ethical problems specific to embryonic stem cells. With any hSC research, however, there are difficult dilemmas, including consent to donate materials for hSC research, early clinical trials of hSC therapies, and oversight of hSC research.
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 Conflicting ethical and legal standard
at another institution
Stem cell clinical trials Risks and benefits of experimental intervention Informed consent
Adult stem cells and cord blood stem cells do not raise special ethical concerns and are widely used in research and clinical care. Pluripotent stem cell lines can be derived from the inner cell mass of the 5- to 7-d-old blastocyst. However, human embryonic stem cell (hESC) research is ethically and politically controversial because it involves the destruction of human embryos. 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. Pluripotent stem cell lines whose nuclear DNA matches a specific person have several scientific advantages. Stem cell lines matched to persons with specific diseases can serve as in vitro models of diseases, elucidate the pathophysiology of diseases, and screen potential new therapies. Lines matched to specific individuals also offer the promise of personalized autologous stem cell transplantation. 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. iPS cells avoid the heated debates over the ethics of embryonic stem cell research because embryos or oocytes are not used. Furthermore, because a skin biopsy to obtain somatic cells is relatively noninvasive, there are fewer concerns about risks to donors compared with oocyte donation.