The possibility of using human embryonic stem cells (ESC) for therapeutic purposes raises serious ethical objections, the most fundamental one being that until recently the only way to obtain ESC was with procedures that necessarily destroyed living human embryos. Due to this, research in this field has been rejected by many scientists, bioeticists, and has been banned by law in several countries. Efforts have been made to find procedures to obtain ESC without destroying embyros or putting them at risk. This paper reviews the scientific, technical and ethical aspects of the different strategies developed for this purpose. Embryo biopsy, ESC obtained from "dead" embryos, ESC produced by "parthenogenetic embryos", ESC obtained by Altered Nuclear Transfer and induced pluripotent cells (iPSC) obtained by direct epigenetic reprogramming of somatic cells are the main five alternative reported in recent studies.
Ventura-Juncá, P., Santos, M., & Larraín, J. (2009). Proposals for embryonic stem cell production without destroying human embryos: scientific and bioethical challenges. Acta Bioethica, 15(2). Retrieved from https://actabioethica.uchile.cl/index.php/AB/article/view/15749