Toppari et al. review the literature on changes in male reproductive health. "The growing number of reports demonstrating that common environmental contaminants and natural factors possess estrogenic activity presents the working hypothesis that the adverse trends in male reproductive health may be, at least in part, associated with exposure to estrogenic or other hormonally-active (e.g., antiandrogenic) environmental chemicals during fetal and childhood development."

• Sperm count: the cautious general conclusion was that a real decline occurred during the 50-year period (examined by Carlsen et al.). "The reason remains unknown, but further examination may provide important clues to the etiology of decreasing sperm quality worldwide."
  
• Testicular cancer: This is now the most common malignancy of young men in many countries. Increases in incidence are demonstrated by data from cancer registries in England, Wales, Scotland, the Nordic and Baltic countries, Australia, New Zealand and the United States. "The observed increase has been approximately 2 to 4% per annum in men under 50 years of age."
  
• Cryptorchidism: A series of studies suggest general increases in cryptorchidism but differences among the studies make it difficult to reach a firm conclusion. "From these three large studies, one can conclude that there has been a significant increase in the incidence of cryptorchidism in England, but the incidence in the racially and ethnically mixed population of New York is similar to that reported in the 1950s in England."
  
• Hypospadias: "Birth data from several reports have indicated a substantial increase in prevalence of hypospadias." As with cryptorchidism, variations in methodology make general conclusions difficult to reach, but increases have been noted in countries where longitudinal data have been studies. The increase has been reported primarily in England, Wales, Hungary, Sweden, Norway and Denmark. No increases have been reported from Finland, Spain, New Zealand, Australia or Czechoslovakia."

Their findings "are compatible with a hypothetical association between exposure to hormone-disrupting chemicals and the induction of cryptorchidism." They caution, however, that methodological limitations "make it necessary to evaluate the results with caution."

Talk to us: email