Human gene therapy: scientific and ethical considerations

Abstract

The term 'gene therapy' encompasses at least four types of application of genetic engineering for the insertion of genes into humans. The scientific requirements and the ethical issues associated with each type are discussed. Somatic cell gene therapy is technically the simplest and ethically the least controversial. The first clinical trials will probably be undertaken within the next year. Germ line gene therapy will require major advances in our present knowledge and it raises ethical issues that are now being debated. In order to provide guidelines for determining when germ line gene therapy would be ethical, the author presents three criteria which should be satisfied prior to the time that a clinical protocol is attempted in humans. Enhancement genetic engineering presents significant, and troubling, ethical concerns. Except where this type of therapy can be justified on the grounds of preventive medicine, enhancement engineering should not be performed. The fourth type, eugenic genetic engineering, is impossible at present and will probably remain so for the foreseeable future, despite the widespread media attention it has received.

KIE: An overview is provided of the current status and ethical implications of four types of gene therapy applications. Somatic cell therapy, designed to correct a genetic defect in a patient's body cells, is easiest and ethically the least controversial. Germline therapy, or insertion of a gene into the patient's reproductive tissue to prevent genetic defects in offspring, will require major advances in knowledge and has ethical implications that are now being debated; the author suggests criteria to be satisfied prior to human experimentation. Enhancement genetic engineering, or insertion of a gene to try to 'enhance' a known characteristic, is scientifically formidable and ethically troubling; the author recommends that it not be performed except for the prevention of serious disease. Eugenic genetic engineering, defined as an attempt to 'improve' complex human traits, is both troublesome and unlikely to be achieved soon.