Reflections and Recommendations
The international project to sequence the human genome was undertaken in the expectation that knowing the sequence will offer new ways to understand and treat disease and disability. If researchers can identify the sequences of genes that code for the body's building blocks, then, it is hoped, they can identify and correct the sequences associated with disease and disability.
So far, researchers have enjoyed only minimal success in using gene therapy to correct such conditions, and no researcher has yet even attempted to use gene therapy to correct genetic impairments in a fetus. Rather, the discovery of abnormal or incorrect sequences has led primarily to the development of genetic tests that can reveal whether a person, embryo, or (in the usual case) a fetus carries an abnormality or "mutation" associated with disease or disability. It is now possible to test for gene mutations associated with some 400 conditions, from those universally viewed as severe, such as Tay Sachs, to those that many might describe as relatively minor, such as polydactyly (a trait involving an extra little finger). The number and variety of conditions for which tests are available grows almost daily.
Today we test for one trait at a time. In the future, however, with advances in biochip technology, it will be possible to test simultaneously for as many traits as one would like. In principle, we will be able to test for any trait we wish that has been associated with any given allele. Not only will the cost of such testing likely decrease as the diagnostic technology advances, but advances in the technology will make it possible to do the testing earlier in the pregnancy. One such technology will isolate the very small number of fetal cells that circulate in the maternal blood. Insofar as these earlier tests will be performed on fetal cells obtained from the mother's blood (rather than from the amniotic sac or chorionic villi) they will be noninvasive. Thus it will be possible to do many more tests, at once, and with less cost to the pregnant woman in time, inconvenience, risk, or dollars, than is now the case.
As the ease of testing increases, so does the perception within both the medical and broader communities that prenatal testing is a logical extension of good prenatal care: the idea is that prenatal testing helps prospective parents have healthy babies. On the one hand, this perception is quite reasonable. Though no researcher has yet even attempted to correct a genetic impairment with in-utero gene therapy, increasingly there are nongenetic approaches to such impairments. At the time of this writing, more than fifty fetuses have undergone in-utero surgery to repair neural tube impairments (myleomeningoceles). Moreover, negative (or reassuring) prenatal test results will reduce the anxiety felt by many prospective parents, and this in itself can be construed as part of good prenatal care. On the other hand, as long as in-utero interventions remain relatively rare, and as long as the number of people seeking prenatal genetic information to prepare for the birth of a child with a disability remains small, prospective parents will use positive prenatal test results primarily as the basis of a decision to abort fetuses that carry mutations associated with disease and/or disability. Thus there is a sense in which prenatal testing is not simply a logical extension of the idea of good prenatal care.
Logical extension or no, using prenatal tests to prevent the birth of babies with disabilities seems to be self-evidently good to many people. Even if the testing will not help bring a healthy baby to term this time, it gives prospective parents a chance to try again to conceive. To others, however, prenatal testing looks rather different. If one thinks for even a moment about the history of our society's treatment of people with disabilities, it is not difficult to appreciate why people identified with the disability rights movement might regard such testing as dangerous. …