This editorial by RN Clayton and others (4 September, p 588) was substantially the same as a commentary by RN Clayton that had appeared earlier in Clinical Endocrinology (1999;50:557-9). The editors of both journals did know that this was so, but the authors and the BMJ failed to make clear that the BMJ article was based on the one that had appeared in Clinical Endocrinology and also failed to seek copyright permission. The BMJ and the authors apologise.