[Ethical, legal and social issues in regenerative medicine].

Regenerative medicine, currently on the stage of research, implies important ethical issues. Current main stream is the embryonic stem cell research which implies destruction of embryo in order to derive ES cells. Is such a use (destruction) of a human embryo, which is called a "germ of human life" in Japanese Society, ethically permitted or not? If yes, in which conditions? Expected clinical use of ES cells and differentiated cells thereof requires therapeutic cloning, on which arises also the ethical permissibility. Such heavy ethical obstacle leads researchers to the utilization of adult stem cells. Recent appearance of iPS cell (induced pluri-potential stem cell) does not escape from ethical issues, although the destruction of embryo is avoided.