This article is based on the closing lecture (by J. Ashby) of the meeting held in Research Triangle Park on January 13-14, 1997-"Assessing the Risks of Adverse Endocrine-Mediated Effects." Several summaries of unpublished data from Zeneca CTL are presented to illustrate concerns over the present absence of agreed criteria for the assessment of endocrine toxicity data. Reference is also made to several points raised by others during the course of the meeting. It is concluded that the substantial challenges currently faced can be met only by strict adherence to the basic principles of good scientific practice, preeminent among which are the needs to confirm data and to respond to them in a cool and dispassionate manner. The wealth of expertise and enthusiasm being devoted to the task in hand, by both governmental and industrial interests, suggests that practical means by which to address the topic of the symposium will be forthcoming in the near future. However, moves to accelerate progress unduly-"to conduct science under the gun"-are already evident. Therefore, if external influences demand that short-cuts must be taken toward achievement of the goals set out in the Wingspread Statement (Colborn and Clement, 1992), such compromises should be clearly identified in order not to confuse the underlying progress that is already evident in this new branch of toxicology.