Nature Biotechnology responds:

Careful readers will realize that we have already outlined our views on why embryos consisting of about 100 cells with no nervous system are not comparable to people with devastating diseases (Nat. Biotechnol. 20, 789, 2001). We do not share the view that a few microscopic cells are equivalent to a sentient human being just because they might become one some day. As the above correspondence testifies, many do believe this and their viewpoint should be respected.

Our editorial sought to highlight the flaws in the current legislation and the likely repercussions for biotechnology if it is passed in its present form. The moral stance currently taken by the Bush administration against embryonic stem cell research is inconsistent, particularly in the light that the US government currently provides federal employees with financial support for in vitro fertilization (IVF) programs. (Bush actually praised IVF in his August 9, 2001 television address on stem cell research.) It is important to remember that stem cell research does not cause the creation or destruction of a single additional embryo. It uses embryos that are discarded as part of IVF.

To say that a ball of cells no bigger than a pinprick should not be destroyed to allow a grown person to live is cruelly dogmatic. But it is equally clear that we should not let scientists create as many as embryos as they want for no good purpose. The area requires clear and consistent regulatory oversight, something that the present US administration has thus far failed to deliver.

See"ES research and immorality, Correspondence 1" and "ES research and immorality, Correspondence 2" .