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Latest Surrogacy News
Pre-implantation genetic
diagnosis offers hope but prompts ethical concerns
Stanford Report March 3, 2003 BY ESTHER LANDHUIS
It's not science
fiction. Nowadays prospective parents can not only know
the sex of their unborn child but also learn whether it
can supply tissue-matched bone marrow to a dying sibling
and whether it is predisposed to develop breast cancer
or Huntington's disease -- all before the embryo gets
implanted into the mother's womb.
"What I think the
public doesn't understand is that this technology is not
in the distant future," said Stanford law Professor Hank
Greely, kicking off a Feb. 27 conference that explored
the controversial topic at the crossroads of human
genetics and reproduction: pre-implantation genetic
diagnosis (PGD). Presented by the Stanford Center for
Law and the Biosciences, a new program directed by
Greely, the conference drew more than 100 people to hear
a panel of eight nationally known law professors,
bioethicists and biomedical research scientists discuss
whether California should regulate PGD.
The verdict, more or
less, was twofold: Track PGD's safety and success with
greater vigilance, and use the technology to prevent
disease but not to seek perfection.
Pioneered by British
physicians in 1989, PGD is an extension to the
previously developed procedure, in vitro fertilization
(IVF), in which eggs are removed from a woman's ovaries
and fertilized in the laboratory with sperm. Three days
later, when the resulting embryos have grown to the
eight-cell stage, the doctor can pluck a single cell
from each embryo and use PGD to screen the cells for
specific genetic defects and chromosomal abnormalities.
One to four desirable embryos will be transferred into
the woman's uterus for development.
To date, specialists
have performed over 6,500 cycles of PGD worldwide, and
1,000 children have been born from the technology over
the last decade.
PGD can monitor about
two-dozen disorders with specific gene culprits --
including cystic fibrosis, sickle cell anemia, muscular
dystrophy, Tay-Sachs disease and Fragile X syndrome.
Newer techniques also have enabled PGD to detect
chromosomal aberrations that cause Down syndrome and
certain blood cell disorders.
Though these tests --
which cost $2,500 to $4,000, on top of the $6,000 to
$12,000 for IVF -- are most commonly used by couples
with infertility or high maternal age, they have become
particularly enticing to families with previous children
born with genetic disorders. "No one wants to walk the
pathway of throwing genetic dice and hoping they come
out the right way," said Mark Hughes, a molecular
geneticist at Wayne State University in Detroit who
helped pioneer the field of PGD for couples at high
reproductive genetic risk.
But just because we
have the technology doesn't mean we should always use
it, Hughes said. The public seems to agree.
According to a 2002
survey conducted by the Genetics and Public Policy
Center at Johns Hopkins University in Baltimore, more
than 70 percent of the 1,211 respondents nationwide
approved the use of PGD to avoid serious genetic
disease. However, less than 30 percent favored using the
technology to choose a child's sex or other desirable
characteristics, such as strength or intelligence.
For a childless couple
with no history of chromosome X-linked genetic
disorders, the use of PGD for sex selection may seem a
mere luxury. On the other hand, many may feel justified
in applying the technology toward "family balancing" --
for a family who wants a son after having five
daughters, for instance.
However, though family
balancing sounds reasonable enough, it could easily be
construed as a violation of equal rights protection
under the U.S. Constitution, argues Radhika Rao, a
professor at the University of California-Hastings
College of the Law. Rao said it would be difficult to
legislate the use of PGD for sex selection without the
appearance of granting undue favor to couples with many
children. "The problem with contextual decisions is that
they can lead to discrimination," Rao said.
In the early 1990s,
couples began to inquire about using PGD to select
embryos that would produce a tissue-matched child whose
blood could be used to cure a sibling's fatal immune
disease.
While over two-thirds
of the 2002 survey respondents approved the use of PGD
for this purpose, some experts fear that "savior
siblings" could be instrumentalized as a means to the
parents' end. Rebecca Dresser, a Washington University
law professor and member of the President's Council on
Bioethics, raised this concern at the conference and
cited a council report that will be released in about a
month. "How will the donor child be regarded by the
family, especially if the transplant fails?" Dresser
asked.
John Robertson, a
bioethicist at the University of Texas-Austin School of
Law, dismisses this worry. He argued that couples who
are willing to endure such costly and involved
procedures as PGD and IVF for the chance to save an
ailing child are surely committed to being good parents
to subsequent children.
Another concern raised
in the upcoming council report stems largely from the
cost issue. Since PGD is expensive and not covered by
insurance, some fear that its widespread use could
further stigmatize disabled people and increase the gap
between "haves" and "have-nots."
But what really makes
people cringe, perhaps because it is the least tangible
of fears, is the possibility that PGD could one day be
used to not only avoid genetic diseases but also select
for desirable traits, such as athletic prowess or
musical ability. "Designer babies might be possible from
a technological perspective, but biology is going to
prevent it from happening," said molecular geneticist
Hughes. Most of these traits are controlled by multiple
genes, making the odds of creating an embryo with the
"optimal" gene combination nearly impossible from a
statistical standpoint.
"When it comes to
public policy, we have to talk about what's reasonable
in the near term," Hughes said.
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