Toward less confusing terminology in endocrine disruptor research

The realization that environmental contaminants interact with hormone receptors and mimic or antagonize the actions of endogenous hormones led to introduction of terms such as endocrine disruptor, endocrine disrupter, hormonally active chemicals, and hormone mimics into the scientific and lay press. Reports suggesting a link between exposure to chemicals adversely affecting the endocrine system and (1) increasing rates of hormone-dependent cancers (breast, prostate, and testicular), (2) developmental detrimental effects in the male reproductive tract, (3) failing sperm counts, and (4) endometriosis resulted in an explosion of research, regulatory actions, and policy changes aimed at better understanding the hazards posed by these chemicals with subsequent restriction in their use. With increasing concern, there is worldwide action to develop testing strategies to allow for early identification of chemicals possessing endocrine disruptor activity. However, despite an expanding literature and numerous expert panel meetings, there continues to be controversy surrounding how to best define endocrine disruptors, resulting in (1) ambiguous use of the term, (2) confusion in the literature, and (3) publication of contentious lists of chemicals purported to be endocrine disruptors. Herein it is argued in favor of a more restrictive definition with adoption of a less ambiguous term, and in favor of development of a classification system to enhance more effective communication and facilitate appropriate allocation of limited resources in this highly charged area of toxicology.