In recent years, there has been ongoing controversy regarding the bioethical issues of stem cells and the pros/cons of their research. In order to understand the clash of opposing opinions about stem cells, it is important to know the root of stem cells, as well as their functions and scientific discoveries. “Stem cells are essential for the development of organisms. These are non-specialized cells that have the potential to create other specific cell types, such as blood, brain, tissue or muscle cells” (Experiment Resources, 2008). Additionally, injuries or diseases that cause dead cells can be replaced with new healthy cells via steam cells (Houdmann, 2010). It has been shown that “stem cell research strives to achieve the cultivation and nutrition of stem cells, the basic cell of the body, allowing them to be reproduced in other specific parts of the body” (Ganesh, 2010). Stem cells originate in our body; There are three main types of stem cells, namely adult cells, cord cells and embryonic cells (Experiment Resources, 2008). Stem cells are more effective in the fetus than in adults, because it is during the early stages of life that stem cells, via embryonic cells, are new and more active in treatment. First, adult stem cells can be removed from their bone marrow or nervous system via the peripheral system (sensory nerve cells and motor nerve cells). One of the advantages of adult stem cells is that their bone marrow contains a very rich reserve of stem cells. Adult bone marrow is a soft, sponge-like material found in the core of bones and contains immature cells called hematopoietic or hematopoietic stem cells (National Cancer Institute, 2011). However, the downside...... middle of article ......stemcell-17.html.• Experiment Resources (2008). Stem Cell Research – Pros and Cons. Retrieved [October 1, 2011] from Experiment Resources: http://www.experiment-resources.com/stem-cell-pros-and-cons.html• Houdmann, M. (2010). Advantages and disadvantages of stem cell research. Retrieved from http://www.allaboutpopularissues.org/pros-and-cons-of-stem-cell-research.htm• Ganesh, G. (2010). Advantages and disadvantages of stem cell research. Retrieved from http://bootstrike.com/Genetics/StemCells/proandcon.php• CA Cowan. (March 25, 2004), Derivation of human stem cell lines from human blastocysts, New England Journal of Medicine, p.1355 with secondary reference to footnotes 13-17 p.1356• National Cancer Institute. (2011). Bone marrow transplantation and peripheral blood stem cell transplantation. Retrieved from http://www.cancer.gov/cancertopics/factsheet/Therapy/bone-marrow-transplant