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TO JOHN WALKER and all other interested parties . One detail not mentioned in the article about cadavers as a stem cell source: The probable life span of a stem cell (or any other cell) is apparently determined by something called a telomere. They are at the tip of our DNA and every time the DNA replicates, the telomere shortens. It is the clock of our biological system and usually determines when our hair will go gray or when we start to get wrinkles etc. Shortened telomeres indicates a shorter life expectancy. The stem cells from a full grown corpse have shortened telomeres and therefore a short life-expectancy. Using stem cells from a fertilized egg, less then 14 days old, gives us long-life stem cells. In addition, the latest research seems to say that young stem cells area bit more versatile and flexible. The differences points out the need for more research with both. Research is for learning and learning requires more than one approach to a problem -- otherwise you really never know. The discovery that stem cells can be recovered from a corpse is good news and at the same time -- bad news for the research with the cells obtained from eggs surplus to an invitro program. We need research in all directions, but now the guns are loaded against youthful stem cell research. I presume they will gleefully continue to incinerate excess product of the invitro program -- rather than let them go into research. Too bad. Sid Levin