Stem cells are undifferentiated cells which are able to grow in any type of tissue with the specialized function. Stem cells can be obtained from inner cell mass of embryos, bone marrow, umbilical cord and amniotic fluid. Stem cells are involved in development, growth and repair in multicellular organisms. Stem cells are used to treat many diseases such as type-I diabetes, heart diseases, cancer, spinal injuries, arthritis, muscular dystrophy and Alzheimer. It can also be used to make new organs like heart, liver, kidneys, skin, even to produce transgenic animals.