Science and Ethical Values by Bentley Glass

Author:Bentley Glass
Language: eng
Format: epub
Publisher: The University of North Carolina Press
Published: 2018-12-15T00:00:00+00:00

Ethical Problems of Selection

Can anything be done to rid the gene pool of its detrimental genes? Can ethical methods be employed to this end?

The most available method would be to use some form of selection, since control of the mutation process itself is at present beyond us. Artificial selection might be applied to prevent the reproduction of carriers of detrimental genes; or measures might be invented to encourage the reproduction and disseminate more widely the good genotypes. Let us look more closely at these negative and positive measures of eugenic selection.

The first difficulty arises because of the recessiveness of most detrimental genes. Harmful dominant detrimental genes are already kept about as low in frequency in the population as is possible. Most bearers of such genes do not reproduce, and most of the harmful dominant genes are new ones just produced by mutation. Our main problem here is the concern which grows from the steadily increasing ability of medical science to lessen or remove the handicap while the harmful gene itself remains intact, to be handed down and consequently to require more medical attention in each succeeding generation. For example, retinoblastoma is a malignant hereditary tumor of the eye which, unattended, is always fatal. Surgery can prevent the spread of the malignancy and often save the vision of the other eye. Being a dominant, the mutant gene that causes retinoblastoma will be expected to be transmitted to half the offspring of any person with the disorder. The question becomes: if we save the lives of these children with retinoblastoma, should they be sterilized to prevent transmission of the gene? Should they be prohibited legally from having children, without sterilization? Should they merely be advised not to have children? Or should nothing be done about the matter? Unfortunately, the latter is only too frequently the solution, even now.

If we adopt severe precautions against the transmission of a dominant gene like that producing retinoblastoma, where do we draw the line with respect to less severe disabilities? Would you sterilize a person with a dominant gene producing a simple visual defect, for example? The criterion seems to devolve upon the social cost of the remedy, glasses being easy and inexpensive to provide, surgery far more costly.

The majority of detrimental genes in the gene pool are, however, recessive. In this case it is necessary, in some way, to detect the bearer before any measures of selection can be taken. Affected individuals with a recessive trait must have carrier parents, of course, but these form a very small proportion of the carriers in the population who did not happen to mate with other carriers. The real hope, in this situation, is to develop technical methods of detecting the carriers, or heterozygotes, by special tests; for, as a rule, it seems they do not possess quite the normal facility for carrying out the chemical step which is blocked, or partially blocked, in the individual with a double dose of the defective gene.

Many ways of detecting the carriers

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