This blog post examines the ethical issues and scientific potential surrounding somatic cell cloning embryo research for therapeutic purposes, exploring whether it should be permitted.
In July 2016, controversy resurfaced when South Korea’s Ministry of Health and Welfare approved somatic cell cloning embryo research for therapeutic purposes. A somatic cell cloning embryo refers to an embryo created by implanting a somatic cell nucleus into an egg from which the nucleus has been removed and then cultured; it can be differentiated into various cell types. Research on somatic cell cloning embryos continues to advance because these embryos can be cultured into cells that do not regenerate in adults, such as nerve cells. Furthermore, since they are genetically identical to the somatic cell donor, they do not trigger rejection reactions when transplanted into the body.
While opinions are sharply divided on whether to permit such somatic cell cloning embryo research, studies limited to therapeutic purposes, as recently decided by the Ministry of Health and Welfare, should proceed.
First, research on somatic cell-cloned embryos is the only method that can offer new life to millions of patients suffering from incurable diseases. Diseases like Parkinson’s or Alzheimer’s, where nerve cells gradually die off, can have their progression slowed by existing drugs, but a fundamental cure remains impossible. Particularly for patients with irreversible damage to specific areas, such as optic nerve damage from severe cataracts or spinal cord injury from accidents leading to paraplegia or quadriplegia, the only treatment option is transplanting new cells using stem cells.
Opponents of somatic cell cloning embryos agree on the necessity of stem cell therapy but argue that treatment is possible using iPS (induced pluripotent stem) cells or umbilical cord blood stem cells (stem cells from the umbilical cord), making research on somatic cell cloning embryos unnecessary. However, iPS cells are significantly less feasible than somatic embryonic stem cells because they require reverting the cycle of cells that have already completed differentiation. In fact, when the safety metric for somatic embryonic stem cells is set at 1, iPS cells are known to have 1,863 times more genetic mutations. Another method, umbilical cord blood stem cells, suffers from the drawback that the quantity of stem cells within the cord is too small to be sufficient for therapeutic use. Furthermore, it is difficult to apply to individuals who did not store their umbilical cord. Considering these points, permitting stem cell therapy research using somatic cell nuclear transfer is reasonable.
Furthermore, from an ethical perspective, arguments against somatic cell cloning embryo research for therapeutic purposes are insufficient. Concerns raised include potential side effects for egg donors during the egg procurement process and the argument that embryos destroyed during research should be considered living beings. First, the issue of egg and embryo destruction during research can be addressed by regulating the use of leftover eggs from the artificial insemination process of infertile couples. Currently, approximately 10 eggs are extracted at once for infertility treatment, but only 2-3 are actually used, with the remainder frozen and discarded. Limiting the research subjects to these leftover, discarded eggs and requiring voluntary donation from the donors would resolve potential side effects for egg donors and the associated ethical issues.
Another opposing argument—that embryos must be regarded as complete living beings—lacks logical validity. This perspective asserts that embryos should be considered living beings because they possess the capacity to develop into complete life forms and because only embryos can grow into adults. If this perspective were valid, the same logic would require that fertilized eggs, possessing the ability to develop into complete living beings, must also be regarded as complete living beings. According to this reasoning, contraceptive devices that prevent the implantation of fertilized eggs in the uterus would become murder weapons, and those who use them would become murderers. In reality, somatic cell cloning research for therapeutic purposes uses embryos cultured for about 6 to 7 days after fertilization. At this stage, the embryo is merely a cluster of cells the size of a pinhead and shows no signs of life whatsoever. Considering this fact, it is unreasonable to regard the embryo as a complete living being solely because it has the potential to develop into an adult. For this reason, restricting somatic cell cloning research on this basis lacks logical validity.
Somatic cell cloning for reproductive purposes requires broader societal discussion. However, restricting even somatic cell cloning research limited to therapeutic purposes is unwarranted, as the potential benefits of such research are immense, and the ethical issues involved can be resolved simply and effectively. Therefore, somatic cell cloning research for therapeutic purposes should be permitted.
