Search NOVA Teachers

Back to Teachers Home

Harvest of Fear

Classroom Activity

To research and debate the arguments for and against the use of genetically modified foods.

Materials for each team
  • copy of "Are Genetically Modified Foods Safe?" student handout (PDF or HTML)
  • Access to print and Internet resources
  1. The issues of the safety of and need for genetically modified foods are being hotly debated in the United States, Europe, and other countries. To help students understand this complex issue, tell them they have been appointed to brief a special Food and Drug Administration review board about the pros and cons of genetically modified foods.

  2. The board wants to know:

    • All the arguments for allowing the use of genetically modified foods.

    • All the arguments against the use of genetically modified foods.

    • The potential risks and benefits of genetically modified foods.

    • What plants or foods have been allowed or banned in which countries, and why.

    • How these foods are different, and how they are the same, as other products currently being sold.

    • Whether foods should be allowed if they are labeled, and why.

    • Whether some foods should be allowed but not others, and why.

  3. Organize students into groups, based on whether they took notes for or against the use of genetically modified foods. Give each group a copy of the "Are Genetically Modified Foods Safe?" student handout.

  4. Have students use their notes from the program and additional resources to form their arguments. Once students are finished researching, have them present their findings and final recommendations to the board.

  5. When the debates are over, hold a class discussion about whether students would be willing to eat genetically modified foods and why or why not. To conclude the lesson, have students discuss how the decision whether to allow these foods to be grown should be made and who should be part of the decision-making process.

  6. As an extension, have students survey their peers and adults about foods from genetically modified foods. Why would or wouldn't other people eat them? What are their responses based on?

Activity Answer

Currently, most genetically modified foods have been agricultural crops (as shown in the chart below). In addition to crops, some U.S. companies have begun research into genetically modifying fish, including salmon, bass, catfish, and trout. Although some crops and seafood have undergone mandatory or voluntary review by regulatory agencies such as the U.S. Department of Agriculture, the Environmental Protection Agency, and the Food and Drug Administration, none of these products are currently required by the U.S. government to be labeled as being genetically modified.

Other countries that have approved biotech varieties for commercial production include Germany, Switzerland, Canada, China, Argentina, South Africa, and Japan.

Students most certainly have already eaten genetically modified foods without knowing it. Using the program and other resources, students should be able to list and defend arguments for and against the use of genetically modified foods.

Genetically Engineered Crops
This list, drawn from the Union of Concerned Scientists' Web site, provides only a few examples of genetically engineered crops and reasons for modifications.


Engineered Trait(s)

Source of New Genes


resists herbicide

bacteria, virus

chicory (radicchio)

makes male sterile to facilitate hybridization



expresses Bt toxin to control insect pests



resists herbicide

tobacco, bacteria


resists herbicide

arabidopsis, bacteria


resist papaya ringspot virus

bacteria, virus


expresses Bt toxin to control insect pests

bacteria, virus


alters oil to increase stability and reduces polyunsaturated fatty acids

soybean, bean, bacteria, virus


resists viruses

bacteria, virus


resists viruses

bacteria, virus


alters ripening to enhance fresh market value

bacteria, virus

Links and Books


McHughen, Alan. Pandora's Picnic Basket: The Potential and Hazards of Genetically Modified Foods. London: Oxford University Press, October 2000.
Examines some of the basic scientific issues involved in whether genetic modification may turn out to yield harmful or, conversely, beneficial results.


Glausiusz, Josie. "The Great Gene Escape." Discover, May 1998, 90-97.
Explains the promise and criticisms of transgenic food production.

"Seeds of Change." Consumer Reports, September 1999, 41-46.
Relates the work of pesticide and seed companies to link strains and market transgenic plants worldwide.

Specter, Michael. "The Pharmageddon Riddle: Did Monsanto just want more profits, or did it want to save the world?" The New Yorker, April 10, 2000, 58-71.
Describes the biotechnology firm Monsanto, and its influence on agriculture, particularly with its development of genetically modified products.

Web Sites

NOVA Online—Harvest of Fear
Provides program-related articles, interviews, interactive activities, resources, and more.

Biotechnology Industry Organization
Offers the industry's position on food and agricultural biotechnology. Includes discussion on food labeling and government regulation information, and lists products on or coming to market.


The "Are Genetically Modified Foods Safe?" activity aligns with the following National Science Education Standards.

Science in Personal and Social Perspectives

Science Standard F:
Science in Personal and Social Perspectives

Risks and benefits

  • Individuals can use a systematic approach to thinking about risks and benefits. Examples include applying probability estimates to risks and comparing them to estimated personal and social benefits.

  • Important personal and social decisions are made based on perceptions of benefits and risks.

Grades 9-12

Science in Personal and Social Perspectives

Science Standard F:
Science in Personal and Social Perspectives

Personal and community health

  • Personal choice concerning fitness and health involves multiple factors. Personal goals, peer and social pressures, ethnic and religious beliefs, and understanding of biological consequences can all influence decisions about health practices.

Teacher's Guide
Harvest of Fear

Video is not required for this activity