Scientists around the world are uncovering alarming changes in human reproduction and health. There is strong evidence that sperm counts have fallen dramatically. Testicular, prostate and breast cancer are on the increase. Different species are showing signs of feminization or even changing sex. The prime suspect in these findings is the increased exposure to chemicals which can mimic oestrogen and other hormones, chemicals to which we are all exposed, found in plastics, pesticides and countless modern products. In this account, Deborah Cadbury, an Emmy-award winning producer of science programmes for television, examines the evidence and ominous implications for the future of human and other life.