What is a Stem Cell? The term “stem cell” refers to an undifferentiated cell that is capable of developing into other types of cells such as liver cells, kidney cells, brain cells, depending on their surrounding conditions. Every type of cell in the body originates from stem cells that appear during the first few days after an ovum and sperm are united.
The cells used for embryonic research are derived from unused fertilized eggs created during in vitro infertility treatment. An ovum that has been fertilized by a spermatozoon is called a zygote or morula. Once planted into the wall of the womb (usually between day 4 and day 5), the clump of cells is called a blastocyst. Zygotes or blastocysts are unspecific in what type of cells they will become.
Research on blastocyst stem cells offers the most promise because these stem cells are able to replicate themselves and have “plasticity” or the ability to differentiate into any cell type and repair tissues in the body. Adult stem cells do not offer the same promise because they are somatic or limited and can only develop into the type of cells found in the organ from which they are taken. Additionally, not all adult organs contain stem cells; therefore not all organs can be regenerated by using adult stem cells. This explains why adult stem cells are not adequate to regenerate the parts of the body damaged through Alzheimer’s, Parkinson’s, SCI and diabetes.
The main source of controversy to blastocyst stem cell research comes from people who believe that taking stem cells from blastocysts destroys an embryo in the process. This is not true. Scientists can take cells from a blastocyst and coax them into growing additional stem cells without harming the blastocyst. The stem cells of the blastocyst phase are not complete organisms, they are not human beings; they are just cells. Leftover blastocysts are normally discarded. They could be used for research purposes.
