When is a stem cell an embryonic stem cell and not a mature (?) stem cell like found in the cord blood? Is it based on time from conception or some other factor?
Thanks,
Ben
Main Entry: em·bryo
Pronunciation: 'em-brE-"O
Function: noun
Inflected Form(s): plural em·bry·os
Etymology: Medieval Latin embryon-, embryo, from Greek embryon, from en- + bryein to swell; akin to Greek bryon catkin
1 a archaic : a vertebrate at any stage of development prior to birth or hatching b : an animal in the early stages of growth and differentiation that are characterized by cleavage, the laying down of fundamental tissues, and the formation of primitive organs and organ systems; especially : the developing human individual from the time of implantation to the end of the eighth week after conception
The bold definition is the common medical usage.
It is possible for identical twins to be born if the original 1 egg and 1sperm join and then separate into 2 forming embryos. Siamese twins occur when this separation is not complete. A further disfunction of the original embryo can happen when a few of the first cell-divisions does not become a second human but a tumor of different kinds of cells called a teratoma) inside the 1 developing baby. All of these biological facts lead me to believe that the closer a cell is to the fertilization stage, the less differentiation it has - the more potential it has to become anything - so more in the realm of God's work than man's.