After reviewing hundreds of peer-reviewed scientific studies researches have concluded that a growing number of chemicals in pesticides, flame retardants, and certain plastics have been linked to widespread health problems including infertility, diabetes, and impaired brain development.  Exposure to certain chemicals found in industrial and household goods has also been linked in new studies to obesity; to endometriosis, a painful and abnormal growth of tissue on the outside of the womb; and to polycystic ovary syndrome, a significant cause of infertility.