In my opinion,in all studies and practical utilizations of stem cells until now there is a fundamental bias I have already emphasized, also in www.nature.com, (e.g., http://www.nature.com/news/2008/080822/full/news.2008.1060.html?q=2#last-comment http://www.nature.com/news/2008/080604/full/news.2008.875.html?q=2#last-comment) Really, we all agree with considering stem cells as the therapy of future. As a consequence, all around the world, scientists are working on the possible utilization of these cells, in spite of their origin. However, we have to pay great attention to the FACT that every stem cell, including human blood progenitor cell, (not red blood cells, i.e., erythrocytes, which are lacking DNA!)is furnished by both n-DNA and mit-DNA, and thus, from biophysical-semeiotic constitutions view-point, such as cell can transmitt the related predisposition to diseases,if there is the Inherited Constitution-dependent Real Risk, I discovered: diabetes, arteriosclerosis (CAD), osteoporosis,cancer, a.s.o. As I referred formerly (e.g., http://blogs.nature.com/reports/theniche/2008/04/ stemcell_skin_creams_a_san_die.html#comments) before using stem cells in whatever disorders, scientists have to know perfectly biophysical-semeiotic constitutions of stem cell donors, to avoid they may bring about other possibly more dangerous or severe disorders (See also my earlier comment on Washington Post website: http://www.washingtonpost.com/ac2/wp-dyn/comments/ display?contentID=AR2007041101736&start=41 .