Where do stem cells derive from?

Stem cells are all over the human body, some regions more so than others. The most common stem cells used are: embryonic stem cell and somatic stem cell. Embryonic stem cells derive from embryos whom eggs have been fertilized. These stem cells are usually harvested seven to ten days after fertilization from the inner cell mass of the blastocyst. All though embryonic and somatic are the most common used by scientist, other forms of stem cells such as: fetal stem cell, umbilical cord stem cell, and placenta stem cell, are still used.

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2) "Frequently Asked Questions." What Are Adult Stem Cells? [Stem Cell Information]. Web. 13 Mar. 2012. .