Stem cells are biological cells with the ability to differentiate into specialized cells and divide through mitosis, therefore producing more stem cells. Nor a days there have been many discoveries for the uses of stem cells in helping patients with disease such as Leukemia. There are three sources ( 'niches') where stem cells can be found. Embryonic stem cells come from embryos three to five days old. The so-called blastocyst has about 150 cells. These can divide into more stem cells or become any cell in the body, making them pluripotent. This allows the cells to be used in regeneration or repair of unhealthy tissue and organs, as well as form the different cells needed for the development of the organism. Adult stem cells are found in small quantities in the bone marrow, fat and most adult tissues. Recent evidence suggests that adult stem cells can transform into unrelated types of cells, for example, bone marrow cells may produce bone or heart muscle cells; compared to previous belief that adult stem cells could only create similar types of cells. Cord blood stem cells are present in the blood remaining in the placenta and attached to the umbilical cord post birth. The blood is relatively easy to collect and contains Haematopoietic stem cells (HSCs), that can make every type of cell in the blood, such as red, white and platelets; and can be used to treat cancerous blood disorders such as Leukaemia and genetic disorders such as Fanconi anaemia.
Embryonic stem cell research causes a lot of controversy because to obtain the stem cell, an embryo with the potential of life must be killed. The newborn babies are not developed enough to agree and give its approval for the use of its umbilical stem cells. Many people that are against the use of embryonic stem cells for research and therapy say that it is not justifiable to just kill an embryo. However, this could lead to the discovery of new medical treatments that could alleviate the suffering of many people.