Given the ethical arguments that revolve around the status of the embryo, getting consensus on whether human embryo research should be allowed is impossible. Even the major religions disagree. The Roman Catholic Church states that an embryo is a person from conception, Judaism from 40 days, while Protestant churches say that it is neither a person nor a simple object. German law mirrors the Roman Catholic position and has a total ban. French law requires ‘respect’ for the embryo from conception, but gives legal rights only at birth; it has a de facto ban. Britain, Canada and Australia not only authorize embryo research, but allow embryos to be deliberately created for research purposes. So does the United States, where an absurd situation exists in which almost anything goes in the private sector, while Congress bans the use of federal funds for any such research.

The therapeutic promise of human embryonic stem cells — a new era in transplantation and cell therapy will surely emerge from their ability to divide indefinitely and differentiate into all sorts of human tissues — obliges countries to revisit the issue of human embryo research. It has already prompted France's Conseil d'Etat, a sort of Supreme Court, and the US National Institutes of Health to do so. Both have arrived at the same conclusion: that such research should be restricted to embryos left over from in vitro fertilization that would be destroyed anyway (see page 565).

That is a wise and pragmatic position. Whatever one feels about the destruction of a human embryo, there is a major difference between creating embryos deliberately for research and doing research on embryos destined to be destroyed in any case. The two national bodies have usefully reduced the scale of the ethical dilemma. Moreover, which of the following is morally better, to allow spare embryos to be destroyed or to use them for research that could benefit the seriously ill? Ironically, embryo research generally, by improving the efficiency of in vitro fertilization and thus reducing the production of spare embryos, could avoid a future ethical dilemma posed by millions of embryos languishing in cryopreservation worldwide.