As an embryo develops, its stem cells gradually lose potency.Pluripotent stem cells are found in embryos (in the inner cell mass of the blastocyst). They can divide in unlimited numbers and can differentiate into almost any type of cell in the body. They cannot produce the placenta, so a pluripotent cell cannot form a whole organism on its own.Multipotent stem cells are found in mature mammals. They can divide to form only a limited number of different cell types, usually those of one tissue. Stem cells in bone marrow, for example, produce red blood cells, white blood cells and platelets.Unipotent stem cells are also found in mature mammals. They can divide but differentiate into only one type of cell. The example you need to know is the formation of cardiomyocytes (heart muscle cells) from unipotent stem cells. Heart muscle has very limited ability to repair itself, which is why a heart attack causes lasting damage.Potency decreases in this order:totipotent → pluripotent → multipotent → unipotent 
In every case, a stem cell specialises because it expresses only some of its genes. Adult (multipotent and unipotent) stem cells are useful in medicine because they can be taken from the patient's own body, but they are harder to obtain, harder to grow and produce fewer cell types than embryonic stem cells.
In every case, a stem cell specialises because it expresses only some of its genes. Adult (multipotent and unipotent) stem cells are useful in medicine because they can be taken from the patient's own body, but they are harder to obtain, harder to grow and produce fewer cell types than embryonic stem cells.