It is the central problem of development where collections of cells control the growth or genetic expression of individual cells. (religion-online.org)
Until 2009, Saitou's starting point had been cells taken from a live mouse epiblast — a cup - like collection of cells lining one end of the embryo that forms at the end of the first week of development, just before the PGCs emerge. (scientificamerican.com)
Either way, a small collection of cells can hardle be considered a human being. (religion.blogs.cnn.com)