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There is a gradient that corresponds to how well a particular stem cell can differentiate.  

There is a gradient that corresponds to how well a particular stem cell can differentiate.  

The two most common types, adult and embryonic are multipotent and pluripotent respectively. Multipotent means that a stem cell can differentiate into similar types of cells, for instance blood cells only. Pluripotent means that they can turn into any of the 3 germ layer types.<ref>http://learn.genetics.utah.edu/content/tech/stemcells/sctypes/</ref>  

The two most common types, adult and embryonic, are multipotent and pluripotent respectively. Multipotent means that a stem cell can differentiate into similar types of cells, for instance blood cells only. Pluripotent means that they can turn into any of the 3 germ layer types.<ref>http://learn.genetics.utah.edu/content/tech/stemcells/sctypes/</ref>  

Even though embryonic stem cells can differentiate into more cell types than adult, they require the destruction of an embryo. This is why there is such an ethical controversy over them. The pro-life movement says it is akin to abortion.<ref>http://www.frc.org/get.cfm?i=WU09C06&f=PG07J01</ref> That being said there is some research that shows that embryonic stem cells might be obtainable without destruction of the embryo, though this research is not definite yet.<ref>http://www.cmda.org/AM/Template.cfm?Section=Stem_Cell_Research&TEMPLATE=/CM/ContentDisplay.cfm&CONTENTID=12577</ref>

Even though embryonic stem cells can differentiate into more cell types than can adult stem cells, they require the destruction of an embryo which is akin to [[abortion]].<ref>http://www.frc.org/get.cfm?i=WU09C06&f=PG07J01</ref> That being said there is some research that shows that embryonic stem cells might be obtainable without destruction of the embryo, though this research is not definite yet.<ref>http://www.cmda.org/AM/Template.cfm?Section=Stem_Cell_Research&TEMPLATE=/CM/ContentDisplay.cfm&CONTENTID=12577</ref>

There are five categories of stem cells that correspond to their origin in the body:

There are five categories of stem cells that correspond to their origin in the body: