A new approach to testing the genes of early-stage fetuses could radically alter the experience of pregnancy and parenting. And we'd better start thinking about it now-before hype, fear, and the polarized politics of abortion distort the discussion.
The technique being developed analyzes fetal DNA that is collected from women's blood as early as five weeks into a pregnancy. So-called "noninvasive prenatal diagnosis," or NIPD, may hit the market as a test for Down syndrome later this year. Soon after, refinements are likely that will allow identification of fetal genes at thousands of sites; two different research groups published papers claiming "proof in principle" of this prospect last December.
Because NIPD would be less invasive, less risky, and less expensive than the kinds of fetal gene tests now available, and because it relies on a simple blood draw so early in pregnancy, it is poised to become a prenatal game changer.
The fetal gene tests now offered are far from a walk in the park. For amniocentesis, a long needle is poked through your abdomen and uterus to extract amniotic fluid when you're about 15-20 weeks pregnant. Chorionic villus sampling takes a snip of placental tissue, acquired by snaking a catheter through your vagina and cervix at 10-12 weeks. Both procedures carry a 0.5 percent to 1 percent risk of miscarriage.
By contrast, for NIPD you'd simply give a little extra blood at the lab at your first prenatal checkup. There would be no risk at all to you or the fetus. And you'd get the results before you were visibly pregnant, before you'd told your mother or your friends.
Of the 5 million or so pregnancies in the United States each year, only a few percent involve amniocentesis or chorionic villus sampling. Another few thousand fetal gene tests are done on embryos created with in vitro fertilization.
These numbers are relatively small. Even so, the practice of selecting fetuses and embryos with particular genes elicits concerns about the implications for people living with the very disabilities that are often "deselected," about sex selection, and about parental expectations of a "perfect" child. NIPD could send the yearly number of fetal gene tests skyrocketing into the millions, and the level of concern soaring.
Researchers developing NIPD have already established partnerships with biotech companies eager to commercialize it; San Diego-based Sequenom has announced it will make NIPD for Down syndrome available in the fourth quarter of this year. Detecting hundreds or thousands of genetic variations, as opposed to particular chromosomal configurations, will be more difficult (and, at least initially, far more expensive). But researchers working on NIPD are confident that they'll soon be able to do just that.
In other words, NIPD might soon be able to present you with the kind of genetic information about your five-week-old fetus that you can get today about yourself by sending a couple hundred dollars and a wad of spit to one of the "direct-to-consumer" gene test companies peddling their wares online. In both cases, you'd get a report that claims to predict risk for scores of common diseases and "conditions."
But what do such reports mean? Predictions based on genetic testing are often highly misleading. You may learn from your own gene test, for example, that your risk of some condition is 50 percent higher than average-but how important is that if the average risk is only 1 percent? You may be told that you have a genetic variation associated with some disease-but that result may be based on one or a couple of small studies that have since been found wanting. The results look impressive and objective but for the most part their meaning is dubious and their usefulness scant. In fact, an increasing number of medical and genetic experts, and an FDA advisory panel, agree that when it comes to predicting common diseases, gene tests are a waste of money. Responsible medical practice, in this view, would limit gene tests to those that are clinically meaningful and useful.
Of course, some gene test results are helpful and important: If you're planning children, for example, you may want to know if you're a carrier for a serious single-gene disorder such as Tay-Sachs; if close relatives have had breast cancer, you may want to learn whether you have the mutation that significantly raises your risk of the rare familial form of the cancer.
But even with genetically imposed risks that are well established-for example, the genetic variation linked to early-onset Alzheimer's-there are often few if any preventive measures to take. Fetal gene testing, however, is different. It presents an option: terminating a previously wanted pregnancy.
If sequencing large swaths of fetal genomes becomes common, that's a choice millions might face. But how could pregnant women and their partners possibly interpret the results of tests that claim to predict dozens or hundreds of a future child's traits? How, for example, could they "balance" a 25 percent increase in one risk against a 15 percent decrease in another? What would any of us do with information like this, even-or especially-if we knew it to be dubious and misleading?
And what of the broader social concerns? How many parents would choose to terminate a pregnancy because their child might be born with a disability-even if it was one with which many people are living full and happy lives? Would health insurers encourage such tests, or even require them, in order to avoid the costs of special-needs children?
It could get worse. Would we see parents using prenatal testing to try for a boy who'd play basketball with Dad or a girl eager to go clothes shopping with Mom? Would we begin to see offers-like the one in 2009 by a Los Angeles fertility clinic-to test fetuses for hair color, eye color, and skin tone?
Two close observers of NIPD's development, UC Hastings legal scholar Jaime King and Stanford bioethicist Henry Greely, predict NIPD will soon force us to face the "brave new world" questions that "we have been able until now to ignore." In a January Nature article titled "Get Ready for the Flood of Fetal Gene Screening," Greely described the pending situation in appropriately dramatic terms: The "spectre of eugenics will loom over the whole discussion," he noted. And concerns about eugenics "will increase as such testing moves from fatal diseases to less serious medical conditions and then on to nonmedical characteristics."
Though some will object to NIPD largely because it makes greater numbers of abortions likely, its social and moral implications are not well captured by the abortion debate. Fetal gene testing in ballooned numbers and scope will disquiet reproductive rights advocates, disability rights advocates, and many others. Those of us determined to protect abortion rights will need to find ways to prevent frivolous and medically irrelevant genetic testing that could distort our hard-won reproductive freedoms and carry us into the realm of eugenics.
CommentsAdd a Comment
Comment by mybluegenome, May 6th, 2011 3:53pm
Why we don’t have to worry about designer babies:
Children have a way of disappointing their parents in spite of all the parents’ efforts to get them to “turn out” a certain parentally-preferred way. Whether a street musician emerging from a generations long tradition of physicians, or a career service man or woman springing from a 1960s hippie couple, the best-laid plans tend to go so easily awry. Is it so hard to imagine an athletically engineered baby turning out to be a bookworm, much to the chagrin and dismay of his parents? Or a green-eyed blonde coloring her hair auburn and wearing blue contact lenses?
On a societal level, what is admired often swings with the generational pendulum. Mary Pickford’s small, cupid-bow lips gave way to mouths that seem to cover half a face. Since what is rare is often most desired, selection for currently popular traits could assure their passing into mediocrity as they become more common. They could even serve to identify one’s generation, just as thirty years from now there will likely be a booming business in ear lobe reconstruction.
As for disability (with the exception of deaf parents who don't believe their hearing children could learn sign language), I suspect we’d be hard pressed to find many individuals living with congenital disabilities agitating for the birth of more people with the same limitations just to make themselves more socially acceptable. As an acquaintance of mine with Becker MD says, “Does it hurt? No. Does it suck? Yes.”
Comment by watchdogonscience, Apr 29th, 2011 2:06pm
I found the references in the link. Thank you.
Comment by watchdogonscience, Apr 29th, 2011 2:02pm
I would appreciate it if you would please include the references to the two scientific papers that you refer to in your article.