The prospects for human germline genetic modification
: scientific and bioethical considerations

  • Kevin Smith

    Student thesis: Doctoral Thesis


    This thesis considers the prospects for human germline genetic modification (HGGM) via a synthesis of scientific and bioethical concepts. Eleven published scientific and philosophical papers form the basis for the thesis. The published work deals with the science, technology and wider implications of gene transfer. A key theme underpinning the thesis is the notion that gene transfer is the central feature of two otherwise disparate bioscience fields - animal transgenesis and human gene therapy. Gene transfer is the route to transgenic animals, and human gene therapy depends upon gene transfer. The thesis argues that HGGM is now scientifically possible: the tools of animal genetic modification - pronuclear microinjection, sperm-mediated gene transfer (SMGT), nuclear transfer, etc - could in principle be applied to humans. However, serious technical obstacles remain to be overcome before HGGM could be considered a practical therapeutic proposition. Nevertheless, it is possible that gene transfer technologies will improve to the point at which it becomes easier and safer to perform HGGM than to carry out embryo pre-screening. In this futuristic scenario of expanded genetic knowledge coupled with effective gene transfer technology, HGGM would become the preferred route. This prospect of genetically modifying humans raises several vexing bioethical issues, including questions of responsibility towards future generations, difficulties of distinction between gene therapy and genetic enhancement, and the spectre of eugenics. Of the many philosophical approaches available to deal with such issues, utilitarianism is an internally consistent and highly consensible ethical system, and it is an approach that is often employed (explicitly or implicitly) in medical decision-making. This thesis argues for and adopts utilitarianism as a valuable, albeit imperfect, philosophical approach with which to address such issues. The utilitarian argumentation in this thesis generates several conclusions in the context of HGGM, including that: [a] the development of effective SMGT technology would largely nullify ethical concerns based on cost and access; [b] the embryo manipulation, genetic sequence alteration and animal experimentation entailed by the development and application of HGGM are all ethically permissible; [c] the notion of risk to future generations, although real, is not unique to HGGM, is likely to be technologically manageable, and is thus of lower ethical salience than prima facie consideration may suggest; [d] HGGM for enhancement (rather than for therapy) would be justified where used as prophylaxis against disease or disadvantage; and [e] the use of HGGM for entirely non-medical enhancements is unlikely to have positive utility, and is thus ethically objectionable, even in the futuristic scenario of effective SMGT becoming available. The overall conclusion of this thesis is that it would be unethical to proscribe medically effective HGGM. 
    Date of AwardDec 2004
    Original languageEnglish

    Cite this