The existence of stem cells first entered the public domain in 1963 when University of Toronto biophysicists Ernest McCulloch and James Till published their theory and experiment resulting in “Nature” (McCulloch, Till 1963). In the decades after, global initiatives into stem cell research have produced large strides in scientific understanding and use in medical treatments of disease and injuries. However, while many medical researchers believe that stem cell treatments have the potential to change how the human race cares for diseases, there is a loud voice that cries out against a particular practice in stem cell research and treatment. It is this voice that has proven substantial enough to restrict research efforts on a global scale in controversy; specifically human embryonic stem cells.
Stem cells are biological cells found in all multicellular organisms. Through a process known as mitosis, stem cells can divide and differentiate into diverse specialized cell types and then self-renew to produce more stem cells. By definition, the abilities to renew (self-renewal) and to differentiate into specialized cell types (cell potency) are the required properties of stem cells.
Potency is specified into five differentiation potentials, totipotent, pluripotent, mulipotent, oligopotent, and unipotent. Totipotent, or omnipotent stem cells can differentiate into embryonic and extraembryonic cell types and are produced from the fusion of an egg and sperm cell. Pluripotent stem cells are descended from totipotent cells and can differentiate into almost all cells. Multipotent cells can also differentiate into a number of cells, but only those of a related family of cells. Olgopotent stem cells and unipotent are found to have even greater differentiating restrictions (Schöler, 2007). The potency of stem cells is the catalyst for what has become an international controversy.
There are two broad types of mammalian stem cells, embryonic and adult, or somatic. Most somatic cells are multipotent and are therefore limited in what they can be used for. Somatic stem cell treatments have been successfully used for years to treat leukemia and other related blood and bone cancers. There is little controversy regarding somatic stem cell research and therapy as the production of them does not destroy the human donor.
To harvest embryonic stem cells, the embryo is destroyed. Embryonic stem cells are derived from the epiblast tissue of the inner cell mass of a blastocyst, or earlier morula stage embryos (Fox News 2006). A blastocyst is an embryo approximately four to five days old in humans and contains between 50-150 embryonic stem cells. Embryonic stem cells, unlike somatic cells, are pluripotent and when given sufficient stimulation for a specific cell type can develop into each over two hundred cell types of the adult body. Yet it is the destruction of the blastocyst that has inhibited science from being able to progress substantially in this...