In 2006, a research study described something quite extraordinary. A third of male fish in English rivers were in the process of changing sex, from male to female. Such reproductive anomalies are not just limited to fish. In humans, studies show that girls are hitting puberty earlier than ever, and that male infertility is on the rise. Men now have a greater range of reproductive abnormalities, from undescended testes to mutated sperm. In one study, it was found that sperm counts have dropped by 30% in the last fifteen years. The incidence of breast cancer...