11.   Even if scientists did want to use frozen embryos at fertility centers, there would be hurdles to overcome, Gibbons said.

12.   Evidence has been emerging that in some circumstances adult stem cells might be used to achieve the same medical benefits, thus avoiding the need to use embryos.

13.   If one wants to study the process of fertilization itself, one cannot use spare embryos left over from a fertility clinic because they are already fertilized.

14.   In this case, the man wants to use the embryos in the future, perhaps with another spouse.

15.   It plans to begin contacting donor couples soon for permission to use their embryos so Harvard scientists can extract stem cells.

16.   Legal experts say the laws could create problems for scientists who want to use embryos to culture the valuable cells.

17.   Many used their embryos.

18.   Peters and Doerflinger also disagree as to whether researchers could get similar results by using stem cells taken from adults, rather than using embryos.

19.   Sen. Orrin Hatch, R-Utah, last year broke ranks with fellow abortion opponents who oppose research using human embryos.

20.   Scientists who have made some advancements in fighting diseases through research involving aborted fetuses, believe that research using human embryos may yield similar medical breakthroughs.