Embryonic stem cells are derived from undifferentiated cells of an embryo. These cells are pluripotent: that is, they have the potential to develop into almost cell or tissue type. Because of this, they are a valuable tool in researching the development of different tissues and organs, and in modeling genetic conditions. Researchers are also investigating whether embryonic stem cells can be used in cell therapy, or gene-cell therapy, for various genetic and degenerative disorders. The use of human embryonic stem cells in research is an often-controversial topic, and scientists are researching other methods for isolating pluripotent stem cells.