BOOBIES! *SNERK*'''Embryonic stem cells''' are taken from the inner part of a young embryo, also known as a [[blastocyst]]. An embryo reaches the blastocyst stage about 4-5 days after [[fertilization]]. At that point they contain about 50-150 cells. Embryonic stem cells can differentiate into the three "germ layers": [[ectoderm]], [[endoderm]] and [[mesoderm]]. The 220 types of cells in humans are all based on these germ layers. Some scientists, particularly those having pro-choice political views, claim that embryonic stem cells can differentiate better, and divide into greater numbers, than [[adult stem cells]] can. [[Pro-life]] conservatives consider taking stem cells from human embryos, as tantamount to [[abortion]], which they believe to be a hideous and [[evil]] practice. President Bush was pressured by [[Liberal]] [[Scientist]]s into funding stem cell research[http://www.whitehouse.gov/news/releases/2001/08/20010809-2.html].[[category:biology]]