Abstract

The recent successful conversion of adult cells into induced pluripotent stem (iPS) cells through direct reprogramming opens a new chapter in the study of disease and the development of regenerative medicine. It also provides a historic opportunity to turn away from the ethically problematic use of embryonic stem cells isolated through the destruction of human embryos. Moreover, because iPS cells are patient specific, they render therapeutic cloning unnecessary. To maximize therapeutic benefit, adult stem cell research will need to be pursued in parallel with studies using iPS cells. Among the four alternative methods presented by the President’s Council on Bioethics, direct reprogram- ming is the most ethically acceptable. Nonetheless, iPS cells are tainted by their association with the human embryonic stem cell lines, derived in the past, which will be required for their validation. This concern is one that can be resolved. Human iPS cells will serve to stem the tide of human embryonic stem cell research, changing it and diverting stem cell research in a more ethical direction.