Stem cells were discovered around 1981 when the first embryonic cell was born. These cells were discovered by Dr. James Till and Dr. Ernset McCulloch. Many experiments have been conducted, for example by inserting stem cells into the hearts of pigs that had heart attacks, and their hearts would become brand new. For humans, this same experiment also worked on their hearts. Injecting stem cells into the heart can also help humans who have had a stroke. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay Stem cells are cells that can divide and provide offspring that can continue as stem cells, and such cells specialize. Based on what I've read, "Stem cells are a continuous source of differentiated cells that make up the tissues and organs of animals and plants." As for stem cells, there are two types: adult and embryonic cells. In adult stem cells, the cells are usually found in small tissues. On the other hand, embryonic stem cells come from embryos. Stem cells can also be found in different parts of the body in tissues. Stem cells are important because they help keep human cells happy and healthy. According to the Encyclopedia Britannica, "...they have potential in developing therapies to replace defective or damaged cells resulting from a variety of disorders..." They are also important to us because they can help restore bodies that have suffered heart attack, heart disease and diabetes. Human embryonic stem cells are collected from the cell mass in the blastocyst. Although this process requires the removal of the trophoblast, it is harmful because it destroys it for further development. This can also lead to the unnecessary deaths of hundreds of people. Stem cells are useful for us because they help heal both animals and humans. Please note: this is just a sample. Get a custom paper from our expert writers now. Get a Custom Essay There are also stem cells that can be as good as human embryonic stem cells. They are called induced pluripotent stem cells. These cells are adult stem cells that are reprogrammed to have the same properties as embryonic cells, but scientists say they don't yet know whether it is safe to inject them into humans. My opinion on all this is that there should be no research that can destroy these cells, these cells can be used for good and should be continued to treat diseases and injuries.