Advances in the science of human genetics since 1980 (particularly the Human Genome Project) have prompted the development of techniques that identify a growing range of deleterious traits or predispositions. As researchers gain greater knowledge about the genetic components of many diseases or disorders, individuals are enabled to take precautionary measures reducing the chances of contracting an illness or mitigating its effects. In addition, genetic testing may be used to prevent the birth of offspring with a severely debilitating illness or disability.

Individuals, for example, may be tested for genetic traits indicating a proclivity for various forms of cancer or heart disease. If these genetic indications are present, individuals can avoid certain lifestyles or diets, take prescribed medications, or undergo invasive surgical techniques (in rare instances), which may help prevent the onset of cancer or heart disease. Moreover, individuals may also be tested for genetic abnormalities that may be passed on to offspring. Individuals may use this knowledge to inform their reproductive decisions. An individual carrying a recessive gene for cystic fibrosis, for instance, may avoid reproducing, limit mate selection to individuals not carrying the same recessive gene, or use a reproductive technology that employs donated gametes.

Genetic testing may also be used to prevent the birth of offspring with a debilitating illness or disability. Using amniocentesis or chorionic villus sampling, for example, a fetus can be tested for a genetically based condition such as Tay-Sachs syndrome. If the test is positive, parents may choose to prepare themselves to care for a terminally ill child or terminate the pregnancy. In addition, preimplantation genetic diagnosis in conjunction with in vitro fertilization may be employed to test a number of embryos, implanting only those that are unaffected by the deleterious gene.

As genetic testing becomes more sophisticated, it offers great promise for advances in diagnostic and preventive techniques. As the understanding of the complex relationship between genes and environmental factors increases, it is hoped that drugs can be developed that will prevent a wide range of late onset diseases. Some envision a day, for example, when individuals with a genetic predisposition for Alzheimer's disease will be able to take prescribed drugs preventing the onset of the disease, or at least mitigating its effects.

Although genetic testing undoubtedly benefits many people, it also raises a number of important ethical, pastoral, and religious issues. There are concerns over privacy. Some worry that genetic testing will be used to discriminate against individuals in employment or insurance coverage. There are concerns over the moral status of the fetus and embryo. Although prenatal testing may prevent the birth of children suffering from severely debilitating illnesses, the techniques also entail destruction of selected fetuses and embryos. More broadly, genetic testing raises intriguing implications for theological anthropology. How will a burgeoning knowledge of human genetics, as well as the ability to manipulate genes, inform religious accounts of what it means to be human?

See also BIOTECHNOLOGY; DNA; GENETIC DETERMINISM; GENETICS; HUMAN GENOME PROJECT; NATURE VERSUS NURTURE; SOCIOBIOLOGY

BRENT WATERS