A genetic defect occurs when a gene fails to express a certain function or produce a particular protein. Such a defect may cause or be a contributing factor to a debilitating disease or illness. The defect occurs when DNA is miscopied, resulting in what geneticists call a mutation. It should be noted that virtually every human being carries a small number of mutations, but they usually are not expressed in a deleterious manner.
Mutations can be passed from parents to offspring. If only one parent carries a mutated gene it will usually be overridden by a second copy of the gene. If both parents carry the mutated genes, offspring are at risk of being affected. For example, if one parent carries the recessive gene for cystic fibrosis but the other parent does not, there is no risk that offspring will be afflicted with the disease. If both parents carry the recessive gene, however, there is a one-in-four chance that they will give birth to a child with cystic fibrosis. In addition, mutations can occur through exposure to certain levels of radiation or chemicals.
The term genetic defect is falling into disfavor because of its pejorative connotation. To identify a gene as "defective" implies that this determination is made in comparison to a natural, normative standard. Consequently, it suggests that individuals affected by defective genes are themselves defective or inferior human beings. A genetic "defect," however, denotes a statistical abnormality within a given population. The degree to which such an abnormality is judged to be defective is as much a social as it is a medical determination. Short stature, for example, is a "defect" only in a culture that places a high value on being tall.
A principal religious concern is to insure that individuals expressing certain genetic traits that are perceived to be undesirable are not stigmatized or subjected to unwarranted discrimination. A similar concern holds for parents of children with genetically related illnesses (particularly illnesses that could be prevented through embryonic or fetal testing), or communities in which there are high incidents of certain conditions such as sickle-cell anemia or Tay Sach's disease. Moreover, there is also some apprehension that recent advances in embryonic and fetal testing will promote a new and more subtle round of eugenics in which parents will select against offspring with genetic traits judged to be defective or undesirable. These religious concerns are derived from a conviction that the value or worth of an individual is not derived from the presence or absence of genetic characteristics, thereby implying a natural hierarchy among human beings.
The idea of a genetic defect also raises vexing theological questions. For instance, since mutations can be passed from parents to offspring, does this imply that nature is flawed and is itself in need of redemption? But if this is the case, what would a redeemed or perfected nature be like? Or, to the contrary, is the possibility of deleterious mutations the necessary price that must be paid in order to spur evolutionary development within the human species? But if this is true, what is one to make of a God who seemingly requires the suffering of individuals in order to promote the flourishing of the species?
See also Genetic Testing; Genetics; Mutation
cole-turner, ronald, and waters, brent. pastoral genetics: theology and care at the beginning of life. cleveland, ohio: pilgrim press, 1996.
kilner, john f.; pentz, rebecca d.; and young, frank e., eds. genetic ethics: do the ends justify the genes? grand rapids, mich.: eerdmans, 1997.
song, robert. human genetics: fabricating the future. cleveland, ohio: pilgrim press, 2002.
peacocke, arthur. god and the new biology. san francisco: harper, 1986.