STEM CELLS

Stem cells are primal cells found in all multi-cellular organisms. They retain the ability to renew themselves through mitotic cell division and can differentiate into a diverse range of specialized cell types. Research in the human stem cell field grew out of findings by Canadian scientists Ernest A. McCulloch and James E. Till in the 1960s.
See more at Wikipedia.org...

undeveloped structures which are able develop into any of the nearly 220 cell types that make up the human body, and which can theoretically reproduce themselves infinitely.
For more information, read Stem Cell Research: Hope With An Ethical Price Tag in the MD Support Library.