Enoch Powell 's Bill to ban research on human embryos is racing through Parliament. It's supported by a big majority in the House of Commons and massive petitions from the public. But infertile couples and parents of handicapped children are desperately trying to stop it. They see human embryo research as the only hope for avoiding human tragedies in the future. Do these ends justify the means? As Parliament reassembles Margaret Jay reports on this crucial debate - where both sides think they are the best protectors of the unborn child.