Some scientists doubt that xenoestrogens have any significant biological effect, in the concentrations found in the environment.

Neurotransmitters produce most of their biological effect by binding to the active site of a protein receptor.

The sievert represents the equivalent biological effect of the deposit of a joule of radiation energy in a kilogram of human tissue.

Therefore, the equivalent dose was defined to give an approximate measure of the biological effect of radiation.

Such changes are presumed to have little or no biological effect.