It has been hypothesized that endocrine-active chemicals (EACs) may be responsible for the increased incidence of breast cancer and disorders of the male reproductive tract. Synthetic chemicals with estrogenic activity (xenoestrogen) and the organochlorine environmental contaminants polychlorinated biphenyls (PCBs) and DDE have been the prime etiologic suspects. However, results of extensive research on PCBs and DDE does not show a correlation between PCB/DDE exposure and development of breast cancer. Studies also show that sperm count levels vary with demography, and the hypothesized coordinate global decrease in sperm counts and other disorders of the male reproductive tract is not supported by published data. In contrast, testicular cancer is increasing in most countries, and causal environmental/lifestyle factors for this disease are unknown.