Embryo screening for genes that cause disease is already happening. How far will it go?
By Jeanie Lerche Davis
Reviewed By Michael Smith
All the couples are affected by an inherited form of aggressive colon cancer and are getting in vitro fertilization (IVF) treatments to get pregnant. The couples appealed to the Human Fertilization and Embryology Authority -- which governs embryo screening in Britain -- to allow them to select an embryo without the cancer gene.
They have won that right. Now, their child and future generations are unlikely to have the cancer gene.
Could this happen in the U.S.? Are we on a slippery slope leading toward designer babies with "basketball star" genes, green eyes, or curly hair? To find out, WebMD spoke with a few experts.
Embryo Screening Still Evolving
"The use of the technology to prevent disease is wonderful. ... When you're preventing lethal and horrible disease in children, it's a good use," Art Caplan, PhD, director of the University of Pennsylvania's Center for Bioethics, tells WebMD.
"But when you get into hair color and freckle selection, that's a whole different story," Caplan says. "In our market, whatever you can pay for, you can do. We don't have [a regulatory agency] here to stop us from going where money and bias can take us. The prospect for a slippery slope has been handled in England because they have built stairs."
However, fertility doctors in the U.S. do have ethical guidelines that limit the use of embryo screening technology, says Cecilia Dominguez, MD, a reproductive endocrinologist with the Center for Reproductive Medicine at the Emory University School of Medicine.
"Right now, preimplantation genetics is used exclusively for major and small groups of genetic abnormalities like Duchenne muscular dystrophy, which is a devastating disease, costs a lot of money, yet leads to early death of the child," she tells WebMD. "We can prevent this fatal disease, which is very important for families with strong genetics."
David Wolmer, MD, chief of reproductive endocrinology and fertility at Duke University School of Medicine, agrees. "If a family has a known genetic disorder like muscular dystrophy, we feel it is OK to transfer embryos that do not have that gene," Wolmer tells WebMD. "We do the same with families who have cystic fibrosis -- specifically screening embryos for those genes, to try to avoid having a child with that disorder."
Needed: Embryo Screening Review Process
However, says Wolmer, "We need a review process that allows people who aren't just doing it to be self-serving. Some couples are asking for a blanket embryo screening, to look at the huge realm of possibilities. That's the slippery slope to me, that people with no family history of a disease are asking us to take a blanket look at the huge realm of possibilities like Down syndrome, for example, which is a genetic abnormality but not an actual genetic disorder."
It's important "to be very careful at that point," Wolmer says. "We need to look at the family's intent when they request embryo screening. In our society today, different yardsticks are used to measure if this is OK or not -- science, theology, law. I think that an Institutional Review Board process in the U.S. needs to be applied here. We can't lose sight of what is research and what is accepted therapy."
Everyone involved in IVF and embryo screening must consider ethics at every point, says Wolmer.
Embryo Screening Not 100% Accurate
Wolmer brings up another point: Embryo screening is not a perfect process; there is no 100% guarantee. "There's a question whether that one cell may be abnormal, but the others may be normal," says Wolmer. "Also, one abnormal cell doesn't mean the whole trait or disorder will develop."
Ordering up "basketball player genes" or green eyes -- those things just aren't possible with current technology, Dominguez tells WebMD. "Figuring that out from one or two embryonic cells is very tricky. We're not anywhere near the point of being able to do that."
Even after embryo screening for genetic abnormalities, "there's still a chance you're wrong," Dominguez says. "Screening is very difficult to do, and it can only be done in the best labs. Some day we will be able to fully fingerprint an embryo. But even if someone has a cancer gene, there's no 100% certainty they will develop the disorder. There are other factors, like environment, that play into this, too."
Published Nov. 4, 2004.
SOURCES: Art Caplan, PhD, director, University of Pennsylvania's Center for Bioethics. Cecilia Dominguez, MD, reproductive endocrinologist, Center for Reproductive Medicine, Emory University School of Medicine. David Wolmer, MD, chief of reproductive endocrinology and fertility, Duke University School of Medicine.
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