Karl J. Shields, an adjunct Professor of Christian Ethics and Youth Ministry at Luther Bible College has written an excellent, in-depth article on the philosophy which underlies prenatal testing. You can read it in its entirety right here but I do print below a fe provocative excerpts:
"The truth is that even with all the knowledge currently available, genetic testing remains in its infancy. Bounded not only by the limitations prone to all medical tests, genetic tests, particularly prenatal genetic tests, have to withstand the issue of penetrance, the rate of actual expression of the gene. Not all genes are expressed 100% of the time. Accordingly, patients can have an abnormal gene, but if that gene is not expressed, they will not suffer the disorder associated with it. Two additional issues unique to genetic tests concern severity and onset. Even if one could be certain about the positive findings of a test, it is impossible to know how severe the disorder will turn out to be. For prenatal testing, assuming that a child can be conclusively diagnosed as having Down syndrome, we have no way of knowing how severe the disease will be; and there is a considerable continuum to be sure. With many genetic disorders, the time of appearance of the disease is unknown. Without this knowledge, it is difficult—almost impossible—to make any therapeutic decisions based on a prenatal genetic test.
…We need to be very clear about what therapy is currently available for most diseases that can be diagnosed prenatally: none. …The ‘Abortion Assumption’ is quite simply the presupposition, epitomized by the rhetoric above, that, if the results of a prenatal genetic test are positive for a severely disabling or terminal condition, that the parents of that child will—and perhaps should—abort that child.
…Until such time as we have therapies for each genetic ailment for which a test is designed, we have no business administering the test. Furthermore, in the case where there is an existing therapy, such as with spina bifida, the prenatal testing must be determined previously to be medically indicated.”
