Sir

Your Editorial “Too much, too soon” (Nature 435, 538; 2005) deplored the fact that the abstract for our manuscript submitted to Reproductive BioMedicine (RBM) Online became public, before being peer-reviewed, on the same day that a Korean group led by W. S. Hwang announced in a Science paper that it had succeeded in producing eleven embryonic stem-cell lines. We would like to clarify our position in this matter.

On 16 May, we submitted a manuscript to RBM Online that had previously been offered to both the British Medical Journal and The Lancet; both journals had declined it after editorial review, claiming insufficient clinical content. At the time of submission to RBM Online, we were not aware that the abstract would be made immediately available online. Learning of this the next day, we asked RBM Online to remove the abstract to prevent public awareness before publication of the Science study. One of us also met Professor Hwang to inform him of our actions and exchange manuscripts. Our paper has now been accepted for publication by RBM Online and will appear, in full, in August.

On 16 May, UK journalists also became aware of the forthcoming publication in Science and contacted us to ask about our progress with nuclear transfer. We did not comment on the Korean breakthrough in advance of its publication, but felt it natural and necessary to say that we had submitted our work and that it would soon become public. In our subsequent comments, we were very clear that the Koreans had made a major advance, when compared with our own achievement.

We believe the strong interest in our work was not driven primarily by a parochialism that affords prominence to local news, but by the ongoing ethical debate. It is the ethics of human nuclear transfer that keeps embryo research high on the agenda of the UK press and public, not the science. We cannot avoid the resulting close and continuous scrutiny, nor should we.