What Are Stem Cells?:

Stem cells are a special type of cell that can easily divide to create new cells; pluripotent stem cells, which are the subject of most research, can create new cells of various types. Over the last several years, scientists have been optimistic about the possibility of using stem cells to treat a wide range of diseases and other health problems, because stem cells could potentially regenerate damaged tissues and organs. (Source: About.com)

Types of Stem-Cell Research:

While news reports and political debates often use the term “stem-cell research” to discuss all scientific research involving stem cells, the truth is that there are a number of different types of stem cells that are being studied. For example, adult stem cells are often drawn from bone marrow, while umbilical-cord stem cells are taken from the blood that remains in the umbilical cord after birth. Most recently, stem cells have been found in the amniotic fluid that surrounds a baby in the womb. (Source: About.com)

Problems With the Use of Embryonic Stem Cells:

There are insurmountable moral problems associated with the use of embryonic stem cells in research and therapy, and it appears as if the mounting list of practical problems will be impossible for researchers to overcome as well;

(1) The destruction of one human life is leveraged for the good of another . Although society must have compassion for those people suffering from genetic disorders, degenerative nerve diseases and spinal cord injuries, it is ethically suspect to use the termination of one life in order to improve the quality of life for others. Embryonic stem cells at this early stage are destined, through a complex choreographed migration of cells, to form the body layers and tissues of the individual human being. Therefore, removing stem cells from an embryo ends that human life.

(2) ESCR has not lived up to its promise. No study has yet shown that embryonic stem cells will cure any disease with certainty.

(3) The use of ES cells can be dangerous. Not only have embryonic stem cells failed to deliver consistent beneficial results, their use has many downsides. The use of embryonic stem cells requires the lifelong use of powerful anti-rejection drugs, which themselves often have pronounced negative side effects. There is a risk of tumors in the body of the recipient if the injected differentiated cells are contaminated with undifferentiated stem cells. Embryonic stem cells have been associated with the death of nearby healthy tissue, including brain tissue. Finally, embryonic stem cells in cloned animals that appear to be normal have had unforseen instability in the expression of the genes. Even two clones from the same source can have different gene expression.

(4) There is a viable alternative to ESCR. There is growing evidence that the repair and regeneration of damaged or diseased tissues within adult organs can bye achieved by adult stem cells, which provide a rich source of regenerative material. Dr. David Prentice, Professor of Life Sciences at Indiana State University and Adjunct Professor of Medical and Molecular Genetics at Indiana University School of Medicine, says that “Many, perhaps most, organs maintain a reservoir of these cells.” These cells are called “adult stem cells” or “tissue stem cells.”
Many people believe fetal stem cell harvesting is important for scientific progress. Actually, adult stem cell research is far more successful, important, and less controversial:

Source: Youtube.com