Within the last fifty years the incidence of cancer has grown to almost epidemic proportions. Nearly one in two American males contract some form of cancer. Professor Howard looks at the probable reasons behind this, pointing in particular to the rapid rise in chemical pollution. The use of chemicals by industry has grown exponentially since the Second World War (see clip 3, 'Chemical Hygiene'). As a result we are led to absorb into our bodies many thousands of chemicals each year. Some of these are endocrine disrupters which interfere with hormonal activity -- especially in fetuses.