[The use of embryonic stem cells for medical-therapeutical purposes: ethical issues.].

The capacity of self-renewal and differentiation renders stem cells an appealing option for cell replacement therapy. Although stem cells are known to exist in fully differentiated tissues, those derived from embryos have generated greater scientific interest due to their capacity for differentiation. The use of embryos as a source of stem cells raises, however, difficult ethical questions, since removing stem cells from an embryo terminates further development of the embryo. The ethics debate on the use of embryonic stem cells focuses on the biological and ethical status of the embryo and the sanctity of life. This paper reviews various ethical issues pertinent to the use of embryonic stem cells for medical purposes.