What is happening to the human male?Something strange is happening to the human male. The incidence of testicular cancer is increasing dramatically in all the advanced economies on Earth, male infertility has reached epidemic proportions, sperm counts are declining at an alarming rate and paternal impacts on offspring health are becoming increasingly apparent. Notably, the incidence of testicular cancer shows a strong correlation with socio-economic development such that, globally, it has become the major cancer afflicting young males. In parallel with the increased incidence of testicular cancer, sperm counts have been falling across the globe. The reason for this decline in semen quality is uncertain at the present time but it may be an indirect reflection of falling testosterone levels, possibly fuelled by oestogenic factors in the environments we inhabit, the food we eat, the water we drink, the drugs we take, the lifestyles we adopt and the metabolic patterns we experience in affluent society. The resultant oestrogenic load may impact male reproductive health at any point in sexual development from fetal life to adulthood. Controlling the exposures responsible for these impacts on male reproduction is essential because, if current trends continue unabated, it will have as major impact on the future of our species.

How do we escape the trap?Many of the social, biological and environmental mechanisms that are driving down human fertility, are self-reinforcing. They operate to accelerate the rate of fertility loss, not stabilize it. Escape from this downward spiral will involve several initiatives that, working together, may provide a measure of control over the rate and depth of fertility decline. For example, we need a complete overhaul of sex education that recognizes the fragility of human fertility and is not so focused on the prevention of teenage pregnancies. We also need to raise the profile of reproductive toxicology so that we can secure better control over the release of potentially harmful compounds into the biosphere. There is a particular need to control male exposures to oestrogens and to counteract those elements of lifestyle, metabolism and the environment, responsible for creating oxidative stress in both the male and female reproductive tract. Accommodating the ART industry would be easier if we secured a deeper understanding of the causes of human infertility so that ART does not become the default therapy for every couple and, when it is used, that IVF is preferred over ICSI. Finally, we need to engineer new social structures wherein fertility is facilitated and encouraged.