Identity and the ethics of gene therapy.

Some conditions detrimental to human well-being, such as sickle-cell anaemia, cystic fibrosis, muscular dystrophy, Lesch-Nyhan disease and various immunodeficiencies, are genetically determined. One potential means of preventing the development of such conditions is the manipulation of genetic material in the conceptus of an organism which would otherwise develop such conditions. Genetic manipulations could take the form either of excising and substituting genetic material, excising but not substituting genetic material, adding but not excising genetic material or reorganizing existing genetic material. To succeed, manipulation would have to change genetic structure so as to change its informational content. It might be thought, however, that all or some such manipulations would involve causing particular individuals to cease to exist and involve bringing into existence new, distinct individuals. Gene therapy could not, therefore, be a procedure which improved the circumstances of the particular individual to whom it is applied. It might be suggested that once the metaphysics of identity and the facts of gene therapy are understood, certain interesting conclusions concerning the ethics of gene therapy emerge. Some such conclusions have been discussed in this journal by Noam J. Zohar and Jeffrey P. Kahn. More, however, needs to be said about them since neither Zohar nor Kahn draws the correct conclusions. While both have pertinent things to say, neither has given a completely clear account of the metaphysics of gene therapy and so neither has completely traced out the implication of the metaphysics for the ethics of gene therapy. This paper attempts to remedy these defects.