51.   But because the cell lines are derived from human embryos, although ones due to be discarded, opponents of abortion had objected to federal approval of the research.

52.   But Bush has accepted the argument of antiabortion activists who say that human embryo destruction snuffs out a life.

53.   But Congress has imposed a ban on federal financing for research involving human embryos.

54.   But Bush and many others have moral qualms about the research, because the cells are extracted from human embryos that are destroyed in the process.

55.   But Bush this week endorsed a bill that would go much further, preventing the creation of cloned human embryos that are used for research, rather than reproduction.

56.   But fertility clinics that do in-vitro fertilization have vast experience in growing human embryos in the laboratory and have perfected the method.

57.   But human embryos must be destroyed to obtain these stem cells.

58.   But for those same reasons, it is unlikely the House and Senate will agree this year on legislation regarding the cloning of human embryos for so-called therapeutic purposes.

59.   But in most cases a human embryo must be destroyed to obtain them.

60.   But many groups, such as the American Life League, hold that human life begins at the moment of conception and that experiments with human embryos are murder.