There is a lot of interest around the problem of stem cells; a lot of practical discussions, and a lot of moral discussions as well. Whether it is good or it is not good to use them or whether it is religiously condemned is not going to be discussed here. This is meant to make you understand how stem cells could save your life and cure numerous conditions.
Stem cells are primal cells found in all multi-cellular organisms. What makes them different than synthetic tissues is that they are able to renew themselves through mitotic cell division and can differentiate into a diverse range of specialized cell types. That means that stem cells could turn into a tissue or a whole organ through therapeutic cloning. Transplants could be useless because stem cells are able to turn themselves into any tissue. They have the capacity to differentiate into specialized cell types.There are different types of stem cells. Totipotent stem cells are produced from the fusion of an egg and sperm cell. Cells produced by the first few divisions of the fertilized egg are also totipotent. They are able to turn themselves into any tissue. Pluripotent stem cells are the descendants of totipotent cells and can differentiate into cells derived from any of the three germ layers; these could be trained to be numerous tissues. Multipotent stem cells can produce only cells of a closely related family of cells (e.g. hematopoietic stem cells differentiate into red blood cells, white blood cells, platelets, etc.). Unipotent cells can produce only one cell type, but have the property of self-renewal which distinguishes them from non-stem cells (e.g. muscle stem cells). The uses vary.
But the bad thing is that there are numerous technical hurdles which could only be surpassed by intense research. A primary goal of this work is to identify how undifferentiated stem cells become differentiated. We know that this is made by powering the genes, but the exact mechanism remains somewhat blurry. Some of the most serious medical conditions, such as cancer and birth defects, are due to abnormal cell division and differentiation. Probably the most important benefit stem cells could bring is for cell-based therapies. Today, donated organs and tissues are often used to replace ailing or destroyed tissue, but the need for transplantable tissues and organs far outweighs the available supply.