There is a real good german/french documentary on this subject named 'Men in danger':
"A program which looks at some of the factors which may explain why sperm production in males has dropped 50% in 50 years, and explores an important
question currently facing scientists; could chemical molecules in our environment be affecting our ability to reproduce? Aside from the huge drop in the amount of sperm production over the last five decades, scientists have also recorded a dramatic rise in the number of testicular cancers and a disturbing increase in the number of congenital malformations in male reproductive organs - two trends echoed in wildlife studies. This suggests the cause is environmental and not genetic. For Niels Skakkebaek, Danish doctor and researcher, the male reproductive and infertility problems we are currently facing are ‘as important as global warming.' (From France, in English) (Science) M CC WS"