In the realm of prenatal testing, motive determines permissibility. Most prenatal testing is done in order to find and kill preborn children who fail to “measure up” to parents’ and physicians’ high standards. Prenatal testing for this purpose is illicit. However, tests for the purpose of healing preborn children are allowable.

Donum Vitae, The Congregation for the Doctrine of the Faith's 1987 instruction on respect for human life in its origin and on the dignity of procreation, answers all the fundamental moral questions about prenatal diagnosis succinctly and completely:

“If prenatal diagnosis respects the life and integrity of the embryo and the human fetus and is directed towards its safeguarding or healing as an individual, then the answer is affirmative.

“For prenatal diagnosis makes it possible to know the condition of the embryo and of the fetus when still in the mother's womb. It permits, or 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. Thus a woman would be committing a gravely illicit act if she were to request such a diagnosis with the deliberate intention of having an abortion should the results confirm the existence of a malformation or abnormality. The spouse or relatives or anyone else would similarly be acting in a manner contrary to the moral law if they were to counsel or impose such a diagnostic procedure on the expectant mother with the same intention of possibly proceeding to an abortion. So too the specialist would be guilty of illicit collaboration if, in conducting the diagnosis and in communicating its results, he were deliberately to contribute to establishing or favoring a link between prenatal diagnosis and abortion.

“In conclusion, any directive or program of the civil and health authorities or of scientific organizations which in any way were to favor a link between prenatal diagnosis and abortion, or which were to go as far as directly to induce expectant mothers to submit to prenatal diagnosis planned for the purpose of eliminating fetuses which are affected by malformations or which are carriers of hereditary illness, is to be condemned as a violation of the unborn child's right to life and as an abuse of the prior rights and duties of the spouses.”

Some specific areas in which prenatal testing is licit include:

l testing in the last trimester of pregnancy in order to help assemble properly trained personnel and equipment needed for a difficult birth due to abnormalities;

l to prepare for in utero and post-birth corrective measures, including dietary control for a newborn baby with phenylketonuria or galactosemia; and

l to prepare the parents psychologically, emotionally, and financially for the birth of a handicapped child.

Source: The Facts of Life: An Authoritative Guide to Life and Family Issues, by Brian Clowes PhD (Human Life International, Front Royal, Va.). Reprinted with permission.