Vladimir Lenin led the Bolshevik Revolution, helped create the Soviet Union and launched the communist era in Russia. Learn more at Biography.com. Vladimir Lenin was founder of the Russian Communist Party, leader of the Bolshevik Revolution and architect and first head of the Soviet state.
The disadvantages come entirely from the source of stem cells. For embryonic stem cells, a human blastula (the collection of cells that will eventually become a fetus) must be sacrificed. This brings forth an image of sacrificing babies for science, and needless to say, many folks have a problem with that.
Scientists are exploring the different roles tissue-specific stem cells might play in healing, with the understanding that these stem cells have specific and limited capabilities. Without manipulation in the lab, tissue-specific stem cells can only generate the other cell types found in the tissues where they live.