Endocrine disruptor occur from low-dose exposure to exogenous hormones or hormonally active chemicals such as bisphenol A. These chemical can bind to receptors for other hormonally mediated processes. Furthermore, since endogenous hormones are already present in the body in biologically active concentrations, additional exposure to relatively small amounts of exogenous hormonally active substances can disrupt the proper functioning of the body's endocrine system. Thus, an endocrine disruptor can elicit adverse effects at much lower doses than a toxicity, acting through a different mechanism. The timing of exposure is also critical. Most critical stages of development occur in utero, where the fertilized egg
Endocrine disruptor and toddlers ingest more contaminated house dust than the adults they live with, and therefore have much higher levels of pollutants in their systems. Consumer goods are another potential source of exposure to endocrine disruptors. An analysis of the composition of 42 household cleaning and personal care products versus 43 "chemical free" products has been performed. The products contained 55 different chemical compounds: 50 were found in the 42 conventional samples representing 170 product types, while 41 were detected in 43 "chemical free" samples representing 39 product types. Parabens, a class of chemicals that has been associated with reproductive-tract issues,