Well, my embryology class was a looooong time ago---and you may be right, but the stage I have seen cited is the zygote, a "cell produced by the union of egg and spern":(acc. to Tabers' Medical Encyclopedia) which I think would be even earlier than a blastula? Is this correct? >Stem Cells = "Blastula" ? > >Is it not true that the best undifferentiated cells are to be found in the >blastula phase of development? > >If I remember my college embryology from 35 years ago, (and if they haven't >completely changed the field of embryology since then), the egg and sperm >come together, begin to split and form a hollow sphere made up of cells.... >a blastula. At this stage the individuals cells can become anything, >depending on chemical and other conditions and influences ("tropisms") to >which they may become exposed. > >If the blastula is the best source of stem cells, then should the questions >not be focused on the use of blastulas, not embryos. What say you? > >Bill >PWP, New Jersey Camilla Flintermann, CG for Peter 82/70/55 Oxford, Ohio <[log in to unmask]> on PDWebring at http://members.tripod.lycos.nl/genugten/flinterm.htm "Ask me about the CARE list for Caregivers of Parkinsonians ! " And visit the CARE webring at http://www.crosswinds.net/~caregivers/index.html