This is an extremely emotional issue and there are no final answers to a lot of the questions in this debate.
Scientists are strongly divided on potential risks to people and the environment.
But many scientists are surprised that there is opposition to most of the GM foods under development. There has been more publicity in Europe about GM foods than in America. In fact, most Americans have eaten some GM food without knowing it. Once a week, for the duration of this series, we will cover a scientific story or a particular issue that is part of this debate. There has been more emotion than knowledge in many of the disputes.