Under the proper conditions embryonic stem cells have the capacity of differentiating into all somatic cell types of human body. Scientific researches on human embryonic stem cells are holding the promises of new medical treatment for a range of currently incurable diseases which can not be treated by conventional techniques. On the other hand along with its great prospects for medical treatments, stem cell research using human embryos raises some legal and moral issues. In this thesis ethical debates regarding human embryonic stem cells are discussed. For this purpose first the legal aspect of the issue is researched in the framework of Turkish legal system through the beginning of life and excess embryos which are created in in- vitro fertilization (IVF) units. As a result it is clearly understood that human embryos are left in a zone of indeterminacy and the analysis in the thesis suggests a coherent reagularity in health legislation.