One of the most controversial debates in the scientific community concerns stem cell research from embryos. What are stem cells and why are they so important? Embryonic stem cell research is believed to hold the key for better treatments and possible cures for some serious illnesses. Stem cells are primitive cells,and they have the ability to change into many different types of cells. There are over 300 distinct types of cells in the human body. but stem cells are the only types that can be grown into other kinds of cells. This is very useful for scientists and doctors. they hope to grow stem cells too regrow damaged tissue or treat injuries. Using mice,scientists have successfully cured Parkinson's disease,damaged nerve tissue and even diabetes. now the challenge is to do the same with human