Ever wonder what a stem cell really does? What does it
Here is a chart of how a haemopoietic stem cell can differentiate into other types of blood cells. Click on the chart below for a larger view.
From a medical point of view there are three types of Stem Cells that you hear about. (Though there may be others that are less well known)
There is no controversy surrounding this type of Stem Cells. Stem Cells collected from the peripheral blood or bone marrow have been used for decades to do bone marrow transplants and stem cell transplants. Since these stem cells are collected from living persons with no harm done to the donor there are no ethical issues involved. In fact in the case of an autologous transplant the patient themselves is the donor.
These stem cells are collected from the discarded umbilical cord during a live birth. The umbilical cord is a very rich source of stem cells. Nevertheless the quantity is still very small and at this time transplants with this type of stem cells are limited to children or small adults. Science is investigating ways to increase the amount of cord blood stem cells to make this type of transplant available to adults. Much of the research is focused on using two or more cord donations that match, or almost match.
This is the type that is causing so much controversy and an ethical dilemma around the world. Embryonic stem cells are considered the most valuable ones because they are so early in their development they have the potential to become any type of tissue at all (pluripotent), not just blood cells. This means they have the potential to cure a vast array of diseases and injuries.
Yet in order to obtain this type of stem cells, a human
embryo must be destroyed very early in its development.
Usually about one week after fertilization. The cells are
then encouraged to multiply without maturing into any
particular type of stem cell. Clearly this presents
scientists and the world at large with a very difficult
ethical, and moral dilemma which has yet to be solved.
Learn more about stem cells
Visit the "Explore Stem Cells" website.