by William E. May, Ph.D., Senior Fellow
Introduction
It is useful to begin by citing the teaching found in  the 1987 document issued by the Vatican’s Congregation for the Doctrine of the  Faith, Donum Vitae (Instruction on the Respect Due to Human Life in Its  Origin and on the Dignity of Procreation). This document addressed the morality  of both pre-natal screening and the use of therapeutic procedures on human  embryos. Regarding pre-natal diagnosis it affirmed: “pre-natal diagnosis makes  it possible to know the condition of the embryo and of the fetus when still in  the mother's womb. It…makes it possible to anticipate earlier and more  effectively certain therapeutic, medical or surgical procedures. Such diagnosis  is permissible, with the consent of the parents after they have been adequately  informed, if the methods employed safeguard the life and integrity of the embryo  and the mother, without subjecting them to disproportionate risks. But this  diagnosis is gravely opposed to the moral law when it is done with the thought  of possibly inducing an abortion depending upon the results: a diagnosis which  shows the existence of a malformation or a hereditary illness must not be the  equivalent of a death-sentence.” Concerning therapeutic measures applied to the  human embryo it taught: “[O]ne must uphold as licit procedures carried out on  the human embryo which respect the life and integrity of the embryo and do not  involve disproportionate risks for it but are directed towards its healing, the  improvement of its condition of health, or its individual survival. Whatever the  type of medical, surgical or other therapy, the free and informed consent of the  parents is required…The application of this moral principle may call for  delicate and particular precautions in the case of embryonic or fetal life.”  
This shows that pre-natal screening and diagnosis is morally good when used  to be of benefit to the unborn child but is morally wicked when used as a means  to “hunt and destroy” “defective” unborn babies. It also provides the moral norm  relevant to use of therapeutic procedures.
Screening as hunting for  and destroying, if found, “defective” unborn children
When the U.S.  Supreme Court in its 1973 ruling in Roe v WadeBetter  Off Dead: The Ethical Thicket of Wrongful Life, Wrongful Birth and Related Legal  Issues ,” http://culture-of-life.org//content/view/674/1/).  Here it is  important to note that in 1967 the Supreme Court of New Jersey, in Gleitman  v. Cosgrove, soundly rejected a “wrongful birth” suit by the Gleitmans  against their obstetrician Cosgrove on behalf of their son Jeffrey. It declared:  “It is basic to the human condition to seek life and to hold onto it however  heavily burdened….The right to life is inalienable in our society.” The  wisdom  of this Court—a wisdom shared as a basic truth in our society at that time—has  been, of course, declared repudiated by the 1973 Roe v Wade  decision.
This barbaric consequence of legalizing abortion was  illustrated for me a few years ago on a visit to my daughter, Kathleen, in  London. Her husband, James Boardman, a pro-life pediatric neurologist then  finishing his residency, came home sickened one night because a newborn brought  to him was blind in one eye. The needle used for an amniocentesis to determine  whether he had Down Syndrome had pierced that part of the brain where the eye  develops. James told us that invasive procedures which jeopardize the unborn  child (e.g., amniocentesis) are medically unnecessary in medical practice in  which neither the doctor nor the patient are not willing to abort, a judgment  made also by the well-known champion of life Thomas W. Hilgers (see his  essay,“Prenatal and Pre-Implantation Genetic Diagnosis: Duty or Eugenic  Prelude?” in Human Genome, Human Person, and the Society of the Future,  eds. Juan de Dios Vial Correa and Elio Sgreccia, Vatican City: Libreria Editrice  Vaticana, 1999, p. 186).
Morally good uses of pre-natal  screening
Prenatal diagnosis can be very valuable. It can, for example,  discover, by use of sonograms and other modern diagnostic procedures, neural  tube malformations. It is then frequently possible to employ a therapeutic  action on the developing unborn child while still in its mother’s womb.  A shunt  can be inserted into the child’s brain and fluid causing pressure on the brain  drained from it, thus providing great benefit to a child suffering from spina  bifida. At a hearing at the US Senate some years ago sponsored by  pro-life  Senator Gordon Humphrey (unfortunately no longer in the Senate),  I personally  was present at  testimony given by a couple and their physician, with the  child—now born and resting on her mother’s  lap—in which they described the  wonderful surgery that had been done on the child while still in her mother’s  womb, a therapeutic intervention indicated after prenatal diagnosis had shown  that she suffered from a neural tube defect and that fluids were building up in  her cranium, exerting pressure on her brain. This timely intervention was  successful in minimizing the harm this child  suffered.
Conclusion
Thus pre-natal screening can be used in a  morally good was as well as in a morally bad way. It seems unfortunate that most  medical hospitals who respect the sanctity of life and refuse to abort unborn  children deemed “defective” because of the hunt and destroy use of pre-natal  screening do not offer pre-natal diagnostic services. Because of this, couples  most in need of support in obtaining truly therapeutic help that will beefit  their unborn children are sent away. But that support must be to affirm the  sanctity of human life. Prenatal diagnosis offers information to a woman, a  couple; such information is good because it delineates reality.  struck down as  unconstitutional state laws proscribing abortion on the grounds that such laws  violated the “right to privacy” granted to pregnant women and their doctors by  the 14th amendment, the pressure for diagnosing unborn children grew and the  legal penalty imposed on obstetricians for failing to warn or diagnose fetal  anomalies became a driving force in obstetric care (on this see Maggie Datiles,  “
 
