Note: this class of chemicals includes DDT, which some people defend as not very dangerous, and want brought back into use.
ScienceDaily (May 17, 2008) — Higher incidences of congenital anomalies, including cryptorchidism (undescended testicles) and hypospadias, were found in boys whose mothers had higher serum levels of certain organochlorine compounds, researchers say.
About Organochlorine Compounds: Initially lauded for their chemical stability, PCBs (such as Araclor and its congeners) and organochlorinated pesticides such as DDT are lipid-soluble compounds actively produced around the world in the first half of the 20th century. After widespread use in agricultural and manufacturing applications (as plastizers, heat-stabilizing additives for PVC electric insulation, adhesives and paints), they were discontinued in both open and closed uses in the 1970s when health risks became apparent. Lipid soluble, the compounds are absorbed and dispersed to living tissue and, as a result, can have a cumulative effect and cause toxin damage across generations. The United States banned their domestic production in 1977.