The Envelopes


A revised version of an individual lesson plan developed by

David Flatley, Principal, Selden Middle School, Selden, Long Island, NY. (This lesson was developed when Mr. Flatley was Chair of Mathematics and Science at W.T. Clarke Middle School, Westbury, Long Island, NY)

Courses for Which Lesson is Intended:

Biology classes.

Category that Best Describes this Lesson:

Social issues.

Types of Teaching/Learning Activities Employed in this Lesson:

Simulation: students imagining that they have learned specific genetic information about themselves.

Ethics/Values Issues Raised by this Lesson:

Responsible use of genetic information, both by researchers and those who learn the information. Basic questions about just how much we want to know about our future health and behavioral prospects.

Lesson Plan

The specific objectives of this lesson include students being able to communicate clearly the notion that ethics and values issues are central to scientific research and being able to identify at least one ethical concern related to the human genome project.

For a class of 30, 30 envelopes, 30 index cards, and a chalkboard are needed. Before class begins, each index card must carry a "genetic code." "Genotypes" are assigned based on the following distribution:

message     no. of cards     % of class
genotype 1             3                         10

genotype 2             3                         10

genotype 3             3                         10

genotype 4             21                       70

[These percentages are not intended to represent the actual proportion of people who might eventually be determined to have such genotypes. They are used only for classroom purposes to make sure that each genotype has at least a few students wrestling with the problems they pose.]

The teacher should fold each card and seal it in a separate envelope so that the genotype is hidden. The following information should then be presented to the class:

Assume for the moment that, thanks to the human genome project, certain human genotypes can be identified for members of this class. For our simplified example, we will consider only four different possible genotypes, 1, 2, 3, and 4 (described below). Each of these genotypes is related to a different set of human traits. The genotypes, their associated traits and the frequency of the genotype in our class population is listed in the following chart:
genotype     traits                                                                         frequency

1                         75% have tendencies toward extremely violent, perhaps even             10%
                           criminal, behavior.

2                         98% will die before 15 unless given treatment before age 5.               10%
                           Treatments currently cost approximately $3,000,000.

3                         75% have the sorts of mental and physical traits that are                     10%
                           keys to becoming superstar athletes.

4                         No special tendencies have been identified. They all fall within          70%
                           the "normal" range in appearance, ability, and predicted behavior.


The teacher should randomly distribute one sealed envelope to each student and review the prepared information with the class. Then, without opening the envelopes, the following questions can be used to start discussion:

After discussing these questions, students should open their envelopes. Now the teacher can ask: "Considering what your genotype is, would you like to re-think your responses to any of the previous questions?"

All of this could be done orally. Or students could be asked to write answers to one or more of the questions considered before opening envelopes. This might most effectively be done over two class periods, with written answers prepared before the second period.


This "futuristic" lesson can be used to raise students's curiosity about the genome project and some of the ethical, social, political, and legal questions it poses. Some time should be spent discussing the importance of knowing what percentage of those with certain genotypes will develop the traits in question, as well as what factors might contribute to or interfere with their development. This is important because, in most instances the human genome project information we are likely to discover will be in the form of the likelihood, rather than the certainty, that various traits will develop; and there may be much we can do to affect their development.

At the same time, it is important to discuss who should have access to whatever information is discovered. Should insurance companies have access to this information? Should our health care providers? The police? The schools? The children who have these genotypes, or only their parents? Are there limits to what science should be allowed to discover about us? Who should be allowed to conduct this research? Who should pay for it?

For further discussion of these issues refer to Case Study #5: The XYY Controversy, in Chapter 4 of Section I.

Previous PagePrevious LessonNext LessonTable of Contents