TIME: Almanac 1993/TIME Almanac 1993.iso/time/032089/03208900.004

Text File | 1992-09-23 | 12.3 KB | 236 lines

                                                                                SCIENCE, Page 70

The Perils of Treading on Heredity

Uncontrolled tampering with DNA could stir up a host of ethical
dilemmas

By  PHILIP ELMER-DEWITT

    The prospect is intoxicating. By mapping and manipulating
tiny genes, man could conceivably conquer diseases, improve upon
his natural abilities and perhaps even control his own destiny.
But just because miracles might someday be possible does not
necessarily mean that they should all be performed. The tools
of molecular biology have enormous potential for both good and
evil. Lurking behind every genetic dream come true is a possible
Brave New World nightmare. After all, it is the DNA of human
beings that might be tampered with, not some string bean or
laboratory mouse. To unlock the secrets hidden in the
chromosomes of human cells is to open up a host of thorny legal,
ethical, philosophical and religious issues, from invasion of
privacy and discrimination to the question of who should play
God with man's genes.

    The opportunities and dilemmas created by the new genetic
knowledge begin even before birth. It is already possible,
through a variety of prenatal tests, to determine whether a
child will be a boy or a girl, retarded or crippled, or the
victim of some fatal genetic disorder. The question of what to
do with that information runs squarely into the highly charged
issue of abortion. Many could sympathize with a woman who
chooses to terminate a pregnancy rather than have a baby doomed
to a painful struggle with, say, Tay-Sachs disease or Duchenne
muscular dystrophy. But what about the mother of three daughters
who wants to hold out for a son? Or the couple that one day may
be able to learn whether an unborn baby has a minor genetic
blemish? Only the most hardened pro-choice advocate would argue
that prospective parents have the right to abort fetus after
fetus until they get the "perfect" baby.

    Complicating such decisions is the fact that genetic
prognostication will probably never be an exact science.
Technicians may someday be able to determine that a fetus has
a predisposition to heart disease, certain cancers, or a variety
of psychiatric illnesses. But they will not be able to predict
precisely when -- or even if -- the affliction will strike, how
severe it will be and how long and good a life the baby can
expect. As scientists learn to detect ever more minute
imperfections in a strand of DNA, it will become increasingly
difficult to distinguish between genetic abnormalities and
normal human variability. "We haven't thought much about how to
draw the line," admits Arthur Caplan, director of the Center for
Biomedical Ethics at the University of Minnesota. "It is going
to be one of the key ethical challenges of the 1990s."

    History shows that genetic misinformation can be severely
damaging. Take, for example, the supposed link between the XYY
chromosome pattern and criminal behavior. In 1965 a study of
violent criminals in a Scottish high-security mental
institution found that a surprisingly high percentage had a
particular chromosomal abnormality: in addition to the X and Y
chromosomes normally found in men, each carried an extra Y, or
"male" chromosome. The press and public seized on the idea that
these so-called supermales were genetically predestined to a
life of crime. That interpretation proved false. Further
investigations showed that the vast majority of men with the XYY
pattern -- an estimated 96% -- lead relatively normal lives. But
before the matter was put to rest, a variety of measures were
proposed to protect society from the perceived threat. One group
of scientists urged massive prenatal screenings, presumably to
allow parents to arrange for abortions. Others initiated
long-range studies to identify XYY infants and track their
progress over the years through home visits, psychological tests
and teacher questionnaires. These dubious efforts were
eventually abandoned, but not before a group of innocent
youngsters had been unfairly labeled as somehow inferior.

    Adults could be wrongly branded as well. Life- and
medical-insurance companies might one day require that
potential customers have their genes screened, presumably so
that people likely to develop fatal or disabling diseases could
be charged higher premiums, or possibly turned away. Insurers
have already used a similar policy to avoid covering individuals
at high risk for AIDS, a practice now banned in several states.
Unless it is prohibited by law, employers could conceivably try
to guarantee a healthy work force by asking job applicants to
submit to genetic screening. Clearly, there is a potential for
widespread discrimination against those whose genes do not meet
accepted standards.

    Once someone's genes have been screened, the results could
find their way into computer banks. Without legal restrictions,
these personal revelations might eventually be shared among
companies and government agencies. Just like a credit rating or
an arrest record, a DNA analysis could become part of a person's
permanent electronic dossier. If that happens, one of the last
vestiges of individual privacy would disappear.

    Even if genetic information is kept private, the knowledge
gained can be profoundly troubling to the individuals involved.
It is one thing to uncover a genetic enzyme deficiency that can
be effectively treated through diet. But what about people who
fear they have inherited a debilitating disease for which there
is yet no treatment or cure? Some might want advance knowledge
so they can prepare their families and put what is left of their
lives in order. Others might prefer not knowing anything at all.
"We may be able to see into the future," says Doreen Markel, a
genetic counselor at the University of Michigan's Neurology
Clinic. "But ask yourself: Do you really want to know what
you're going to die of?"

    The questions multiply as the science progresses. Thomas
Murray, director of the Center for Biomedical Ethics at Case
Western Reserve University, acknowledges that some people are
worried that a complete map of the genome might somehow
"diminish our moral dignity . . . reduce us somehow to nothing
more than the chemical constituents of our bodies." But knowing
the entire sequence of DNA base pairs is like having the full
musical notation of Beethoven's Ninth Symphony, he says. "In no
way does that knowledge diminish the grandeur of the symphony
itself."

    University of Washington ethicist Albert Jonsen is
concerned that people with grave illnesses might be viewed
simply as carriers of genetic traits. "Rather than saying `Isn't
that family unfortunate to have a schizophrenic son,' we'll say
`That's a schizophrenia family.' " Advocates for the handicapped
fear that in the future the physically afflicted may no longer
be seen as unfortunates worthy of special treatment, but as
"wrongful births," genetic errors committed by parents who
failed to take proper action against a defective gene.

    To speak in terms of eliminating genetic defects is to
tread on slippery scientific and ethical ground. As any
biologist will testify, genetic variety is the spice of life,
a necessary ingredient to the survival of a species. Genes that
are detrimental under certain conditions may turn out to have
hidden benefits. Sickle-cell anemia, for example, is a
debilitating blood disease suffered by people of African descent
who have two copies of an abnormal gene. A person who has only
one copy of the gene, however, will not be stricken with anemia
and will in fact have an unusual resistance to malaria. That is
why the gene remains common in African populations.

    Even to label genes as defective can be dangerous. In the
19th century new discoveries about heredity and evolution gave
rise to the eugenics movement -- a misguided pseudo science
whose followers thought that undesirable traits should be
systematically purged from the human gene pool. Believers ranged
from the American eugenicists of the early 1900s, who thought
humans should be bred like racehorses, to the German geneticists
who gave scientific advice to the leaders of the Third Reich,
instructing them on how the species might be "purified" by
selective breeding and by exterminating whole races at a time.

    No geneticist today would even talk about creating a master
race. Scientists are careful to point out that experiments in
gene therapy will be aimed at curing hereditary disease and
relieving human suffering, not at producing some sort of
superman. But what if people want to use the technology to
improve genes that are not defective but merely mediocre? Could
genetic engineering become the cosmetic surgery of the next
century? Will children who have not had their genes altered be
discriminated against?

    Scientists agree that it would be reprehensible to try to
move too far in the direction of genetic uniformity. "The
improvement and enhancement of genetics to some sort of optimum
is not a function of medicine," observes the University of
Minnesota's Caplan. "Very soon the medical fields are going to
have to state clearly that their primary goal is the elimination
and cure of disease and disability."

    The possibilities for gene therapy will be limited for the
near future. If gene transplants are performed on tissue cells
-- bone-marrow cells, for instance -- the altered genes will die
with the patient; they cannot be passed on to any children the
patient might subsequently have. Someday, however, it may be
possible to change genes in germ cells, which give rise to sperm
or eggs. If that feat is accomplished, the new genes would be
transmitted to one generation after another.

    That is what most frightens the foes of genetic
engineering. If biologists can change the course of heredity,
they can try to play God and influence human destiny. In 1983
activist Jeremy Rifkin, a longtime opponent of many kinds of
genetic research, and several dozen theologians mounted an
unsuccessful effort to persuade Congress to ban all experiments
on human germ cells. Said Avery Post, president of the United
Church of Christ, at the time: "We're not good enough or
responsible enough. There is no question about it. We will abuse
this power."

    No geneticist is currently planning to transfer genes to
human germ cells. Even though mankind has been playing God since
biblical times, rearranging the germ lines of crops and farm
animals to suit human needs, researchers do not advocate
extending such genetic tinkering to people. But medical
scientists have an obligation to protect humanity against
disease and pestilence. Once it becomes possible to eradicate
a gene that causes a fatal disorder, and thus keep it from
passing to future generations, it will be criminal not to do so.
As director of the Human Genome Project, James Watson contends
that the research has a crucial humanitarian mission. Says he:
"The object should not be to get genetic information per se, but
to improve life through genetic information."

    Fortunately, the most ardent supporters of genetic research
are the first to admit the potential for abuse and see the need
for ground rules. Many ethicists and scientists who have studied
the issues agree on certain basic principles:

    Individuals should not be required to submit to genetic
testing against their will.

    Information about people's genetic constitution should be
used only to inform and never to harm.

    The results of a genetic assay should be held in strict
confidence.

    Genetic engineering in humans should be used to treat
diseases, not to foster genetic uniformity.

    Knowledge is power, the saying goes. It can be dangerous,
but it can just as easily be used wisely. "I do have faith,"
says Case Western's Murray. "Not that the judgment of people is
always right, but that eventually we will preserve a good
measure of fairness and justice. If we can absorb Copernicus and
Galileo, if we can absorb Darwin and Freud, we can certainly
absorb mapping the human genome."

    One thing is certain: the genie cannot be put back into the
bottle. Like atomic energy, genetic engineering is an
irresistible force that will not be wished or legislated away.
The task ahead is to channel that force into directions that
save lives but preserve humanity's rich genetic heritage.