AN EMERGING TOPIC: It has been hypothesized that exposure to certain chemical compounds in the environment could lead to reproduction and development anomalies. VARIABLE MECHANISMS OF ACTION, SUSCEPTIBILITIES AND EFFECTS: The incriminated environmental agents could have several targets in the endocrine system. As hormones play a cardinal role in regulating differentiation during early stages of life, developing organisms would be particularly vulnerable. AN EVALUATION METHODOLOGY: Although the hypothesis of endocrine perturbation is theoretically plausible, solid scientific data is still lacking to conclude that environmental compounds have a deleterious effect in humans after low-dose exposure. The ubiquitous nature of the intermediary metabolism of these compounds, the existence of critical periods of life, the complexity of the cell processes involved, and the differed timing of the effects make it difficult to assess risk. Current research is being conducted to develop specific methodologies to better understand this risk. AN INTERNATIONAL EFFORT: Different international and national entities have organized scientific committees with the task of identifying chemical compounds susceptible of perturbing endocrine function. In 1998, an international convention set up regulatory control of sales of certain chemical compounds.