31.   Stem cells of various sorts are present throughout the adult human body, but those found in embryos are particularily versatile.

32.   Supporters argue that cloned embryos are only clumps of cells that could cure a wide range of deadly and debilitating diseases.

33.   That would halt research at a point when the embryo is a tiny, formless mass of cells with no developed nervous system.

34.   The American Society for Reproductive Medicine, which represents the fertility clinics, has said creating embryos would be morally justifiable in certain limited cases.

35.   The cells are extracted from human embryos when the embryos are five or six days old, still small enough to fit on the head of a pin.

36.   The chosen embryo was both free of the disease and a compatible donor.

37.   The cloned embryos would be perfect genetic matches for patients, who could then receive tissue transplants, with no need for anti-rejection drugs.

38.   The embryos are cells at the very dawn of human development.

39.   The embryos are not in any case the equivalent of an intact, full-term fetus that can become a living person.

40.   The embryos were extra ones donated by couples in Wisconsin and Israel who had undergone the infertility treatment and who no longer wanted them.