Contents | Chapter
Dr. Lu's Patients Have
the Right to Be Tall
(or do they?)
Dr. Lu has two patients with the same problem, but she isn't
sure if she should treat them both. The patients, Tim and Rico, are seven-year-old
boys who are very short for their age.
When you fall ill, you sometimes need to go to a doctor to find out what
is wrong. At the doctor's office, they will observe your symptoms and examine
your body. They may look inside you using X rays and other equipment. They
may do tests on your blood or urine, to see whether anything is wrong with
your cells or the way your body is working. They also may do something
else: look inside your cells at your genes. Every day, genetic research
is being applied in new ways to help diagnose health problems.
Tim will never grow much taller than 5 feet because his body does
not produce enough of a hormone needed to grow. When he is an adult, Tim
will be much shorter than his mother and father, who are both closer to
Rico will never grow much taller than 5 feet either. Rico will be
short because he has inherited his body build from his parents, who are
both about five feet tall.
Researchers have used genetic engineering to produce a growth hormone.
Both sets of parents want this growth hormone to be prescribed for their
sons to help them grow taller. They want this because they feel that there
are many advantages to being tall.
Dr. Lu realizes that genes play a role in the height each child will
reach. Tim will be short because of a single mutation in one gene that
instructs for the production of a growth hormone. Rico will be short due
to the many genes he inherited from two short parents. Despite this difference,
the end result for both boys will be the same.
Dr. Lu is thinking about prescribing the hormone for Tim, but not
for Rico. However, she wonders if she is being fair. If you were Dr. Lu,
what would you do?
Someday, it also may be possible to correct health problems by
going inside cells to the genes. Treating disorders by altering genes is
called gene therapy. It will work something like this. When you
have an illness, your doctor will determine whether the problem is caused
by a mutated gene that is giving out faulty instructions for the production
of a needed protein. If so, new DNA will be inserted into some of your
cells. This new DNA will correct the gene's instruction for making the
protein. If the treatment is successful, the repaired gene in these cells
will go to work, giving out the proper instructions so that the protein
Cystic fibrosis is one disease that researchers are trying to cure through
gene therapy. In Chapter 4, we explained that with CF the lungs become
clogged, making it hard to breathe. The problem is caused when a gene gives
faulty instructions for producing the protein that helps make the mucus
lining of the lungs.
Doctors are trying to move corrected copies of this gene into the lung
cells of CF patients, using a virus. We usually think of a virus
as causing illness. However, the kind of virus used in this experiment
is harmless. Using special techniques, copies of the corrected gene are
inserted into the virus. Then the virus is sprayed up the nostrils of the
patients. The virus attaches to cells inside the nose and lungs and reproduces
by inserting part of itself into them. As it inserts its DNA into these
cells, it also inserts the corrected gene. Hopefully, the corrected gene
will take over in enough cells so that the needed protein is produced.
Gene therapy is also being tried with a disorder called severe combined
immunodeficiency (SCID). This disorder occurs when the body fails to
produce a particular enzyme. Without the enzyme, a person cannot make the
special blood cells that resist infection. A few young children with this
disorder have been treated with cells altered to carry the genetic instructions
for making the enzyme.
It is too early to tell whether these treatments will work. Hundreds
of research trials are under way using gene therapy. None has yet been
able to claim complete success, although a lot of valuable things are being
learned. Even so, gene therapy is still so experimental, that it is being
tried only on patients who have diseases for which there are no other cures.
It's also important to realize that gene therapy may never work for
a wide range of health problems. It may be too difficult to use genetic
therapy for disorders that involve the actions of many genes. Also, for
many health problems in which genes are involved, the genes are only partly
responsible for what's wrong. In such cases, gene therapy may be only part
of the solution. Gene therapy also may be of little use in treating medical
problems that have no genetic cause, such as broken bones or wounds caused
by an accident.
The kind of gene therapy we have talked about so far will be for people
who are already born. That is, it will fix some of the genes at work in
a part of a person's body. It will not affect the genes that a person passes
on to the next generation. However, even that may be possible some day.
The kind of treatment that could change the genes you pass on to your children
is called germ-line therapy.
From Chapter 2, you may recall that germ cells are the special cells
that divide to form eggs and sperm. Researchers are figuring out how to
alter the DNA in your germ cells. If they succeed, this means that they
would be able to alter the DNA that is copied and passed on through your
eggs (if you are female) or your sperm (if you are male).
With germ-line therapy, genes could be "corrected" in the egg or sperm
you are using to conceive. The child that results would be spared certain
genetic problems that might otherwise have occurred. It may even be possible
someday to use germ-line therapy to remove a disorder from your family
tree forever. Your children would not inherit the problem gene. Neither
would your grandchildren or your great-grandchildren.
Germ-line therapy is a long way off. However, it already is very controversial.
In fact, it is so controversial, that the U.S. government currently does
not allow federal funds to be used for germ-line experiments on human patients.
Most people who have thought about germ-line therapy do not oppose the
idea of using it to help families rid themselves of the genes for terrible
diseases. However, they are concerned because making changes to the germ
line of one person can affect many people who are that person's descendants.
They say that perhaps it is not right to make changes to a germ line, because
some of the people who will be affected are not even born yet and therefore
cannot give their consent. An even bigger concern is that making changes
to germ cells could disrupt the development of the embryo or fetus in unexpected
ways. For these reasons, most people feel that germ-line therapy should
not be used until we fully understand its long-term effects and have addressed
the ethical questions it raised.
Although gene therapy is still experimental, in other ways genetic research
already has changed how medicine is practiced. This is because of the genetically
engineered drugs that are now available through biotechnology.
Take, for example, the treatment of diabetes. In the past, the only
way to get insulin for diabetics was to process it from pigs and cattle.
Then researchers learned how to make insulin by cloning the human gene
that carries the instructions for making insulin.
Cloning and other techniques of genetic engineering have had many positive
results. Genetic engineering has helped increase the supply of medical
products and lower their costs. It has resulted in new drugs being created.
Another benefit of genetically engineered materials is their purity. This
is important, since there have been cases in the past where medical products
processed from animals or human donors carried disease.
Human growth hormone is one of the medical products that can now be
manufactured through genetic engineering. In the past, its only source
was recently dead human donors. Getting human growth hormone in this way
was difficult and controversial. It also did not recover very much of the
hormone. Furthermore, there was a risk that hormones from dead bodies might
be contaminated and pass on diseases. With genetic engineering, human growth
hormone can now be produced in pure form in large quantities. This has
made the hormone more widely available. That's why Dr. Lu faces her decision
on treating Tim and Rico, the boys who are both very short.
Without treatment, neither boy will end up much over five feet tall.
There is nothing unhealthy about being only five feet tall, of course.
However, Dr. Lu may feel that Tim should have treatment because his one
gene is not working normally. She may even feel that Rico should have treatment
because his normal genes will cause him to be abnormally short.
Suppose, however, that Dr. Lu's next patients are children who will
grow to be only 5 foot 4 inches or 5 foot 6 inches. If their families want
them to be taller, what should she do? Where does she draw the line? It's
even possible that as people hear about this growth hormone, they will
demand it for their tall children to make them even taller. What will Dr.
Lu do for families that want their boys to be seven-foot-tall basketball
One thing that Dr. Lu has to consider is that the treatment is not quick
and easy. For it to work, the boys will have to receive a great many shots
over several years. The treatment appears to have side effects. For example,
it may cause bad cases of acne that leave scars. Also, the treatment doesn't
guarantee how much the boys will grow. Studies suggest that the treatment
works better for children like Tim, who has a single mutated gene responsible
for his stunted growth, compared to children like Rico, who has many genes
contributing to his short build. Even so, all those years of shots may
give Tim a few extra few inches and Rico even less.
Dr. Lu also must consider the fact that the treatment would be performed
on children. Genetically engineered drugs are still new. It's possible
that there are long-term side effects that no one knows about yet. Since
Tim and Rico are children, they can't make the decision themselves. On
the other hand, Dr. Lu can't wait until they are adults for them to decide,
because the treatment needs to start while they are still growing.
So perhaps the decision rests with the parents. Yet before she turns
the decision over to them, Dr. Lu must consider one more thing: whether
the problem of being short is really a medical problem that deserves treatment.
The parents may feel that if their children are taller, they will have
more success. The question remains, however: What needs changing, the boys
or the idea that short is bad and tall is good?
Genetic research is uncovering new ways to treat, cure, and even prevent
many kinds of diseases and disorders. However, it is quite likely that
the new techniques will be used in ways that don't always have to do with
In Dr. Lu's story, two families wanted a genetically engineered drug
for their children not because the children were sick, but because they
wanted them to be taller. Genetically engineered drugs, gene therapy, and
germ-line therapy could open the door for lots of people to change how
they or their children look. People may seek genetic treatments that will
make them look younger, have more hair, or lose weight. If researchers
ever figure out how genes control for behavior and ability, people may
try to use that knowledge, too, for example, to improve their I.Q. or their
athletic ability. There is nothing new about people wanting to improve
themselves. What will be new is the opportunity to use genetic techniques
to make those improvements.
There is a word that describes the use of genetic knowledge to improve
the human race. The word is eugenics. "Eugenics" comes from a Greek
word meaning "wellborn." For many people, the word has a bad ring to it.
This is because eugenic ideas often have been used by people to claim that
they are better than others.
That is what happened in Nazi Germany. Hundreds of thousands of people
were sterilized, and millions more were killed, in concentration camps
because the Nazis wanted to "purify" the German race. They targeted Jews
and also Gypsies, homosexuals, and many others. Many of these people were
victims of cruel and inhumane experiments designed to prove Nazi eugenic
Even before the Nazis came to power, however, eugenic ideas were very
popular in the United States and Europe. Many people in the first half
of the 1900s believed that crime, poverty, and other social problems were
the fault of people with "bad blood." They also believed that people of
"poor stock" were reproducing more quickly than people of "good stock,"
leading to the decline of the human race.
The people who held these ideas considered themselves to have "good
blood." They were for the most part well to do, educated, white, Protestant,
and descended from northern Europeans. People with "bad blood" were people
who were different from them -- poor, uneducated, of color, Catholic or
Jewish, and descended from southern Europeans.
Some people who held eugenic ideas also were scientists. These scientists
conducted research to support their theories. For the most part, their
research was badly done and affected by their beliefs about the kinds of
people who were good or bad. Even so, many states in the U.S. adopted laws
to control "overbreeding" by people of poor stock. For example, thousands
of prostitutes and black women were sterilized on the grounds that they
Eugenic ideas are popular even today. China has a law that forbids mentally
retarded people from marrying if they have not been sterilized. Singapore
offers cash rewards to well-educated women who have babies.
In the U.S., the eugenics laws from the first half of the century are
no longer on the books. However, the beliefs still persist. One new way
these beliefs are expressed is in the idea that poor people are poor because
they have poor genes. This idea is not based on good science, but that
does not prevent the idea from catching on.
A "Super" Race?
Some people fear that once we have the tools to tinker with our genes,
we may be tempted to use them to design a "super" race of human beings.
As a practical matter, this will probably never be possible. It's one thing
to use gene therapy to get rid of an unwanted gene or two. It's a whole
lot more to pick and choose the whole range of genes that make an ideal
First of all, you would have to decide what is the ideal. Then you would
have to figure out which different genes come into play to make that ideal.
And then you would have to figure out how to raise all the children so
that they grow up to be ideal. Even if you could solve all those issues,
you would still need the political power to make it happen. A grand plan
to "improve" the human race would involve the government in personal childbearing
and child-rearing choices. This would certainly be opposed by many and
difficult to enforce.
So we may never make a "super" race. But in more limited ways, we may
be able to shape our future. We may be able to spare ourselves and our
descendants from terrible diseases and disorders. We also may be able to
select some of the traits of our children. But do we want to? We also need
to think about whether these choices will be available to everyone. It
probably won't matter too much if some people don't get to select the eye
color of their children. However, it will matter a great deal if some day
only poor people suffer from terrible genetic disorders because they are
the only ones who cannot afford genetic medicines and gene therapy.
We also need to worry about whether genetic technology will make us
less accepting of people who are different. For example, if it is possible
to predict and prevent the birth of a child with a gene-related disorder,
how will we react to children we meet who have that disorder? Will we think,
Why is this child alive? Will we think, Why didn't the parents "do something"
to prevent the child's condition? Will we resent the medical and special
education costs spent on the child? Will we put pressure on parents not
to have "defective" children?
One of the important beliefs upon which this country was built is the
idea that we are all "created equal." We know from the study of our genes
that we are indeed very much alike. But we are not genetically equal. And
no matter how much we tinker with our genes, we never will be.
However, that doesn't mean that we don't all have equal rights. It's
important to remember that what we believe in is as important as what science
allows us to do.
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 SciLi@aaats.org.