Table of Contents | Chapter 2
Martin Needs Medical
|Genes determine physical traits like eye color.|
At the same time, you have traits, or ways of looking, thinking, and being, that you share with some other people on earth. For example, you may look like your father or share your mother's sense of humor.
You also have traits that you share with every other person on earth. For example, every person has blood, lungs, and a brain. All things considered, you are more like every other person on earth than you are different from them.
One way that scientists know this to be true is by studying our genes. Genes are units of information inside the cells of your body. They contain the instructions for making cells and for doing the work that goes on inside them. It is through the genes that traits are handed down from parents to offspring, in a process called heredity. Genes help decide your size, build, coloring, and other features. They make you male or female. Researchers believe that genes also play a part in how you think and behave and in your body's health.
The human body is very complicated, so it makes sense that it needs a lot of instructions. Scientists don't yet know the exact number of genes that humans have, but they think that the number is somewhere around 80,000. Inside each one of those genes are distinct chemical ingredients called bases. The bases are linked together in long chains, with thousands or millions of bases per gene. Millions more bases link the genes together. Add up all these small parts, and you have 3 billion separate pieces that make up the human instruction book. Yet of these 3 billion pieces, only about 3 million are different from person to person. These are the parts that make you unique.
Now, 3 million is a huge number, but it is not much compared to 3 billion. What this means is that all human beings are built from nearly the same set of instructions. We are all really quite similar.
How does a set of instructions work to create humans and other forms of life? This is the subject of a field of science called genetics. Genetics is the study of how traits are passed down, or inherited, from one generation to another. It is the study of how each living thing is similar to others of its kind, but also unique.
For hundreds of years, people have known that traits can be inherited. They observed how looks were passed down from parents to children. They noticed how illnesses run in families. They used their understanding of inheritance to breed plants and animals. But no one really understood how this passing down of traits actually worked.
Then, about 400 years ago, the microscope was invented, and for the first time, scientists could see objects as tiny as a cell. They discovered that living things are created from cells of their parents. They also learned that living things grow when their cells divide to form new cells. As more powerful microscopes were invented, scientists could even look inside cells to watch what happened as they divided and reproduced.
Scientists also learned about heredity by studying plants, fruit flies, and other forms of life, or species, that produce several generations in a short period of time. They discovered patterns in the way that traits are passed down in a species from one generation to the next. And they learned how species change over time, trait by trait, in a process called evolution.
Slowly, scientists began to unravel the mystery of genetics. Today, powerful computers and other modern research tools are helping scientists learn a great deal more, at a much faster pace. They are figuring out how genes work to do what they do. And they are uncovering the functions of specific genes.
These discoveries are teaching us a great deal about the genetic instructions that construct and operate the human body. This new information will give us new opportunities to control the destiny of our bodies. But at the same time, it will force us to face new and sometimes difficult choices. Some of these choices will be have to be made by individuals or families. Other choices will be made by all of us together, as a society.
To get an idea of the many choices that come with the new genetic information, consider Martin, the boy who is albino.
Martin is albino because his genes do not give the right instructions for his body's production of pigment, the dye that colors the skin, eyes, and hair. The result is that Martin is very pale. He must avoid the sun because he is at high risk of sunburn and skin cancer. Strong light hurts his eyes, and his vision is poor, so he needs glasses.
Suppose researchers discover a way to treat Martin's genes so that they give the proper instructions for producing pigment. This kind of genetic treatment may be possible someday. It would mean that Martin's skin and eyes would regain color. He no longer would have to stay out of the sun all the time. Plus, he wouldn't stand out from other children. These changes could make a big difference in Martin's life.
Do you think Martin should have the genetic treatment? In other words, do you think being albino is a medical problem that needs fixing? Or would you say the treatment is more along the lines of a nose job or face-lift -- something nice, but not necessary?
Your answers to these questions are important, because genetic treatment could be expensive. Should health insurance pay for it? Maybe you say yes. However, the cost of this treatment for people who are albino may drive up the cost of health insurance for everyone. Would that change your answer?
Think about the choices Martin's mother would have to make. If she loves Martin the way he is, how does she explain a decision to have him treated? But if he is unhappy with the way he is, how does she explain a decision not to treat him? Also, many medical treatments have side effects. What level of risk is acceptable?
Perhaps when Martin grows up, he will decide that he wants to prevent his children from having the problem he has had. He may decide to have any baby of his tested before it is born, to make sure it is not albino. If it is, he and his wife could choose to have an abortion and try again. What do you think of this choice?
Adoption is another choice Martin and his wife could make, instead of risking bearing children who are albino. With adoption, the children would not be their own, genetically. But Martin and his wife could raise the children as their own, and they would not be albino. What do you think of this choice?
It's possible that when Martin grows up, he will be comfortable with how he looks. He may not care whether his children are born albino. In fact, he may even prefer it because then they would look more like him. What do you think about this? Do you think it is wise to let children into the world with problem skin and poor eyesight if we know how to keep this from happening? Another way to ask this is, Should Martin be prevented from having children who are albino? Who are we to say no to him?
Finally, there is the question of where society should put its time and money. Perhaps along with research into the treatment of genetic conditions, we should put equal effort into teaching children (and adults) to accept those who are different. What do you think?
These questions are just the "tip of the iceberg" when it comes to genetic research. There are many more. One way to explore the topic is to look at it in terms of the ethical, legal, and social issues. Ethical issues concern what is moral or right. Legal issues concern the protections that laws or regulations should provide. And social issues concern how society as a whole (and individuals in society) will be affected by events. To really get into all of these issues, you first need to know some of the basic science of genetics. That comes in our next chapter.
|Table of Contents | Chapter 2|
Your Genes, Your Choices is a publication of Science + Literacy for Health, a project of the AAAS Directorate for Education and Human Resources. The publication was funded by the U.S. Department of Energy. The website was built by Mike Wooldridge. Send feedback to SciLit@aaas.org.