Sources of human embryos for stem cell research: ethical problems and their possible solutions.

UNLABELLED Using different sources of human embryonic stem cells for research raises different ethical problems. Experimenting on embryos created for in vitro fertilization but left unused, or embryos, created specially for research raise ethical questions. In the first case--whether using "spare" human embryos for research means a lack of respect for the beginning of human life, and in the second--whether creation of embryos for research is morally worse than experimentation on already created, but unused human embryos. The possibility of therapeutic cloning also raises a question whether it is ethical to create human embryos for therapeutic purposes. When balancing the possible benefit of embryonic stem cell research inventing new therapies, and the ethical problems, raised by this research, a question is posed whether there are any equally effective alternatives to research on viable human embryos that could avoid or at least decrease these problems. The aim of this literature review is to present the main arguments for and against using different sources of human embryonic stem cells and to acquaint with possible alternatives to human embryo research. METHODS The literature review of the last five years. CONCLUSIONS The currently used sources of human embryonic stem cells and research methods raise ethical objections in certain sectors of society, based on the arguments for the need of respect for the human embryo. However, there already theoretical possibilities of embryonic stem cell research exist, the application of which could decrease the ethical objections to such research. This should be taken into consideration when making decisions on the regulation of embryonic stem cell research. But so far there is no consensus on these questions, and the article presents both favorable and unfavorable opinions regarding this research.