An epistemological inquiry into the endocrine disruptor thesis.

For about a decade the term endocrine disruptor has become synonymous with a new research initiative that has been investigating the effects of hormonally active xenobiotics on biological systems. The scientific thesis behind the new research initiative is discussed and it is argued that there is a need for more emphasis on theory development and conceptual clarification that will give coherence to a field experiencing a rapid growth of empirical studies. Reflections on scientific methodology in this field will also help clarify whether endocrine disruptors symbolize a new etiology of chemically induced disease or represent variations of traditional chemical toxicology.