Also known as undifferentiated cells, stem cells are a unique type of cells that have the ability to divide rapidly and differentiate into a wide range of specialized cells. Thus, stem cells have two characteristic features: one — the ability to divide ceaselessly through innumerable cycles of mitotic cell division, and two — the potential to differentiate into different cell types. Stem cells are either totipotent (that is they can form embryonic cells), or pluripotent (that is they can form all kinds of cells found in the body). Unipotent cells that have the self-renewing capability, and multipotent cells that can differentiate into closely related cells, are also sometimes referred to as stem cells.
On the basis of their origin, stem cells can be divided into two broad categories: embryonic stem cells and adult stem cells. While the former is obtained from the inner cell mass of the blastocyst, the latter comes from the adult tissue like the bone marrow, adipose tissue, amniotic fluid, placenta, umbilical cord blood and so forth. Under proper conditions and requisite stimulus, embryonic stem cells can develop into any one of the 200 different types of cells present in the body. Adult stem cells, on the other hand, can either create cells like themselves or differentiate into more specialized cells.
Adult stem cells are primarily used to repair and regenerate human tissues and organs. On the contrary, embryonic stem cells are used not just for repairing purposes, but also for the treatment of debilitating diseases like multiple sclerosis, diabetes, spinal cord injury, heart disease, Parkinson’s disease, and the like. They are also used for healing wounds and burn injuries. Despite of their boundless potential in the treatment of different kinds of human diseases, a lot of controversies are associated with embryonic stem cells basically because of their place of origin.
The opponents of stem cell research believe that embryonic stem cells are obtained after destroying the blastocyst, which has the potential to develop into a complete human being. However, in reality, blastocyst is nothing but a mass of cells. The different tissues, organs and systems can form out of these cells, but as no differentiation has taken place, therefore it cannot be equated with a human being. Furthermore, each day, hundreds of women undergo abortion, which has been legalized in several countries. These discarded blastocycts can easily be used to stem cell research, which will be beneficial for the entire human race.
Another issue that the opponents of stem cell research raise is that by modifying the stem cells, the scientists are fiddling with the nature. If we take into account, in-vitro fertilization, then this issue seems to be baseless. During in-vitro fertilization, the egg and sperm are fertilized in an artificial environment, and the developing embryo is placed in the uterus for further development. In-vitro fertilization is never seen as a manipulation of any kind. Few of us know that in the entire procedure only a handful good embryos are selected, the remaining are discarded. These discarded blastocysts can be used for stem cell research. Thus, stem cells, irrespective of their origin, can be used for the benefit of the human race, and all the controversies associated with embryonic stem cells are unconvincing and unjustified.