Based on definition of World Health Organisation the Commission has proposed that a substance is an endocrine disruptor if it meets the following conditions:

• it is known to cause an adverse effect on human health, demonstrated by a change in the morphology, physiology, growth, development, reproduction or lifespan of an organism, system or (sub)population that results in an impairment of functional capacity, an impairment of capacity to compensate for additional stress or increased susceptibility to other influences.
• it has an endocrine mode of action.
• the adverse effect relevant for human health is a consequence of the endocrine mode of action.

Commission confirmed that “in practice, it will be very difficult to demonstrate ‘conclusive evidence’ of causality”. Hence, it made a proposal to use a concept of “biological plausibility” or reasonable evidence when demonstrating causality.