The Pope urged researchers, instead, to concentrate on stem cells from adults. Some studies have suggested adult stem cells can be as medically useful as the stem cells taken from embryos. The adult cell research does not involve the death of a human embryo. But American researchers who are studying both the adult cells and the embryonic cells say that both paths must be followed if the medical miracles possible from stem cells are to be achieved.
Stem cells are biological building blocks.
They are the ancestral cells for all the body's tissue. Stem cells differentiate, or evolve, into the heart, lung, skin and all the other organs in the body. Researchers believe that by learning to direct or control the direction of change in stem cells they will eventually be able to grow new organs or to renew ailing body parts with injections of special stem cells. The single cell formed when an egg is fertilized by sperm. This cell can develop into a complete individual.