ADULT VS EMBRYONIC
ADULT: This stem cell research can be carried out by extracting cells form the bone marrow or from the peripheral system of the bone. Bone marrow extraction is painful and can cause damage, but yeilds a rich supply of stem cells. Adult cells are most often used when replacing cells in an adult and extracting cells from the bone marrow of that same adult. The matching DNA makes them better than stem cells from someone else.
UMBILICAL: This method simply taking cells from the umbilical cord during pregnancy and storing them as insurance in case the baby should ever need them in the future.
EMBRYONIC: The stem cells are taken when an embryo has around 100 cells, most of which are stem cells because they have not yet started to differentiate. The stem cells are removed, killing the embryo, and kept in a lab to grow them into large numbers of cells that can then be used. They are also very versatile because they are so undeveloped in this stage.
The ethics of stem cell reasearch relate mostly to the use of embryonic stem cells. Some people believe that using human embryos for research is the same thing as killing them, and is unethical. Advocates argue that the embryo is not really human yet, simply because it has no human features. Some studies have also shown a correlation between use of embryonic cells for treatment and the formation of cancer. However, these risks are somewhat overridden by the versitalit and durability of embryonic cells, and the fact that adult cells have other risks such as toxins absorbed throughout the lifetime of the donor. Stem cells have been successfully used to treat diseases, so one people say that the benefits outweigh the ethics. However, the fact remains that using embryonic cells is extinguishing a human life before it is old enough to help itself.
GENE THERAPY and GENOMIC MEDICINE