Preimplantation genetic diagnosis (PGD) tests early-stage embryos produced through in vitro fertilization (IVF) for the presence of a variety of conditions. One cell is extracted from the embryo in its eight-cell stage and analyzed. Embryos free of conditions that would cause serious disease can be implanted in a woman's uterus and allowed to develop into a child.
PGD allows couples at risk of passing on a serious genetic disease to have a child that is fully genetically related to them and that does not carry genes for the disease. It does not involve the manipulation of genes in embryos; rather, it selects among embryos.
To date, PGD has been most widely used to prevent the birth of children with chromosomal diseases such as Down's Syndrome, and with other genetic disorders, including Tay-Sachs disease, cystic fibrosis, sickle cell disease, Huntington's Chorea, and Cooley's anemia.
People who oppose the destruction of human embryos in general are necessarily opposed to PGD; however, for some, PGD is preferable to aborting a fetus affected by a medical condition that has been identified through prenatal screening.
Preimplantation diagnosis and selection is also controversial because it can be considered a eugenic technology. Many disability rights organizations, in particular, have been critical of its uncontrolled use, and point out that the definition of "disease" is to some extent subjective. Most disability rights advocates who criticize PGD and prenatal screening nonetheless support abortion rights. They believe that a woman should be allowed to decide whether or not to have a child at a given time, but not to base this decision on the traits of the particular embryo.
Many people fear that PGD will be used to select a child of a preferred sex. PGD could also be used in attempts to select a future child's cosmetic, behavioral, and other non-disease traits.
However, the genetic laws of independent assortment make it difficult for PGD to be used for any traits that depend on two or more genes. Thus, PGD provides an alternative to germline modification as a way to prevent the births of children with serious genetic diseases, most of which are single-gene disorders, but does not open the door to escalating and species-altering applications.
(Image courtesy of the Association of Reproductive Health Professionals)
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>> CGS >> Letter to HFEA on Sex Selection
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"Update on the Push for Sex Selection," Genetic Crossroads
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"Human Cloning Advocate Pushes Fertility Clinics to OK Sex
Selection," Genetic Crossroads (#20, October 3, 2001)
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>> Archive >> Issue #20
Amy Dockser Marcus, "Ensuring Your Baby Will Be Healthy" The Wall
Street Journal (July 27, 2002)
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Aaron Zitner, "A
Boy or Girl, You Pick, " The Los Angeles Times (July 23,
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Gina Kolata,
"Fertility Society Opposes Choosing Embryos Just for Sex Selection,"
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Gina Kolata,
"Fertility Ethics Authority Approves Sex Selection," The New York
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Susan Sachs,
"Clinics' Pitch to Indian Émigrés: It's a Boy," The New York
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Off-Site Links
Erik Parens and Adrienne Asch, in consultation with the working
group on Prenatal Testing for Genetic Disability. The Disability
Rights Critique of Prenatal Genetic Testing: Reflections and
Recommendations, The Hastings Center Report, September-October
1999.
http://www.thehastingscenter.org/oldsite/pdf/supseptoct_99.pdf
American Society for Reproductive Medicine fact sheet on PGD
http://www.asrm.org/Patients/FactSheets/PGD-Fact.pdf
The Committee on Women, Population, and the Environment (CWPE) is a
multi-racial alliance of feminist activists, health practitioners
and scholars. They have been actively involved in the critique of
the use of PGD for sex selection. The committee has also maintained
a commitment to critical engagement with other genetic and
reproductive technologies.
http://www.cwpe.org/
More Information
Analysis:
Examine the social, cultural, and economic landscape
Perspectives:
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