The moral value of induced pluripotent stem cells: a Japanese bioethics perspective on human embryo research

In contemporary Japan, at least in the field of regenerative medicine, human induced pluripotent stem cells (hiPSCs) are given no moral status and are treated in a purely instrumental way. However, some authors have mentioned the potentiality of hiPSCs in that 'tetraploid complementation' would make it possible to create humans directly from human embryonic stem cells (hESCs) and hiPSCs. A blastocyst consists of inner cell mass (ICM) cells and a trophoblast. The tetraploid complementation technique demonstrates that hESCs and hiPSCs both have the same capacity as ICM cells. If ICM cells, hESCs and hiPSCs were all provided with a trophoblast or a substitute with the same function, which would work as a placenta, they would have the same potential to develop into embryos, fetuses and adult human beings. Thus hiPSCs could be regarded as potential humans. However, no authority or guideline in Japan has specifically considered the status and use of hiPSCs. In this paper, I will address the extent to which the existing recommendations apply to hiPSCs and develop a novel Japanese bioethical perspective on the status of hiPSCs and its implications for hiPSC research, based on the reasoning in the report, 'The fundamental way of thinking in treating the human embryo' presented by the Bioethics Committee of the Council for Science and Technology Policy in 2004, and broader consideration of Japanese culture.