What is so special about embryonic stem cells?
Embryonic stem cells are different to adult or tissue-specific stem cells. Embryonic stem cells are the only stem cell that can be grown in large numbers in the laboratory and retain the ability to grow into any type of cells including nerve, heart muscle, bone and insulin-producing cells. Embryonic stem cells are often referred to as the ‘master’ stem cell. Tissue-specific adult stem cells are few in number, hard to isolate and are difficult to grow outside the body. Adult stem cells, such as skin and bone marrow stem cells, can usually only grow into a limited number of cell types. For instance, skin stem cells can be grown in the laboratory to make more skin, but cannot make new heart muscle or other cell types. There is recent scientific evidence to suggest that some adult stem cells such as nerve and blood stem cells may also have the ability to grow into other cell types. While this exciting prospect may provide an alternate source of some cell types, this option is currently sti
