The UCB stem cells are pluripotent cells that retain the ability to divide and to differentiate into any cell type. Stem cells are also called tribal pluripotent cells.

  The great physiological significance lies in two very important traits:

1. They are undifferentiated cells with the ability to continuously divide,
2. We can drive their differentiation towards a specific cell type under appropriate experimental conditions.

 The stem cells are divided into two major categories:

1. Embryonic, encountered in the early stages of embryo development
2. Adult, found in a limited quantity in the tissues of the adult.

The embryonic stem cells differ from adult for their ability to multiply (divide faster and therefore can be handled more efficiently), such as the ability to differentiate into more cell types. This enables embryonic stem cells to have potentially much broader therapeutic applications.

On the contrary, the adult stem cells differentiate into particular cells of the tissue from which originated for example, stem cells of the brain, differentiated under normal conditions into neural cells and not in cells of the heart.

http://stemcells.nih.gov/info/basics/basics1.asp
Hans R. Schöler (2007). "The Potential of Stem Cells: An Inventory". in Nikolaus Knoepffler, Dagmar Schipanski, and Stefan Lorenz Sorgner. Humanbiotechnology as Social Challenge. Ashgate Publishing, Ltd. p. 28. ISBN 0754657558.
"Stem Cell FAQ". US Department of Health and Human Services. 2004. http://www.hhs.gov/news/press/2004pres/20040714b.html. Retrieved 2010-03-07.
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