Ethics assessment as an adjunct to risk assessment in the evaluation of developmental neurotoxicants.

The conduct of experimental studies in humans is governed by a body of principles whose main precepts have evolved over the past few decades. Three of these provide the foundations for judging the ethical adequacy of such an experiment. One addresses the question of who receives the benefits of the research and who bears its burdens (justice). A second requires that the research maximize the potential benefits to the subjects and minimize the risk of harm (beneficence). The third, the source of guidelines for informed consent, requires that subjects enter into the research voluntarily and with adequate information (respect for persons). Unlike research conducted to evaluate drugs, however, environmental exposures to potentially toxic chemicals do not survey those exposed for their consent, nor do they provide an appropriate calculus for measuring risks and benefits, which typically involve two different populations. Especially for exposure to developmental neurotoxicants, where the risk-benefit incompatibility can be so striking, another element may need to be incorporated into risk characterization: a process of ethics assessment. A scheme for doing so can be derived from the procedures of fuzzy logic, which allow rules to be formulated that are applicable to ethical principles. Such an approach incorporates some of the tenets of the precautionary principle.