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Actualizable Potential, Reproduction, and Embryo Research: Bringing Embryos into Existence for Different Purposes or Not at All


In several papers, John Harris has argued that if


it is morally permissible to engage in reproduction, whether natural or artificial, despite knowledge that a large number of embryos will fail to implant and quickly die, then


it is morally permissible to produce embryos for other purposes that involve killing them, for instance, to harvest stem cells that may be used to save lives.

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1. Harris J. The ethical use of human embryonic stem cells in research and therapy. In: Burley J, Harris J, eds. A Companion to Genethics. Oxford: Blackwell, 2002; Harris J. Stem cells, sex, and procreation. Cambridge Quarterly of Healthcare Ethics 2003;12:353–72; Harris J. Sexual reproduction is a survival lottery. Cambridge Quarterly of Healthcare Ethics 2004;13:75–90.

2. It may seem extreme to claim that there can be an obligation not to engage in reproduction. However, a real-life analogous example would be Lesch-Nyhan Disease. Such babies lead short agonizing lives marked by self-mutilation. Prior to genetic screening, couples with this gene stood a one in four chance of having a child with this condition. If genetic testing were not available, it seems arguable that it would be wrong to risk bringing into existence a child with Lesch-Nyhan Disease in order to have a healthy child. If you do not find this example convincing, consider a case in which the probabilities are reversed such that the chance of having a healthy child is only one in four.

3. However, we can imagine the situation in which reproduction is different and a number of unsuccessful implantations would be causally necessary to make a woman ready for successful implantation. This would make the parallel between reproduction and the circumstances of stem cell research closer, for in the latter case embryos are plainly used as a mere means. But the case of the four deformed babies should warn us that this modification is not necessary for it to be wrong to engage in natural reproduction. As our example of the severely disabled babies showed, it is not crucial that the existence of the four be causally necessary to bring the one into existence.

4. This is intended as a contribution to answering a question Harris raises about how to characterize instrumentalization in cases where the individual, allegedly instrumentalized, is not competent to consent for himself or herself; see note 1, Harris 2004.

5. Savulescu J. The embryonic stem cell lottery and the cannibalization of human beings. Bioethics 2002;16(6):508–29.

6. Savulescu J. Embryo research: Are there any lessons from natural reproduction? Cambridge Quarterly of Healthcare Ethics 2004;13:68–75.

7. See note 1, Harris 2003:366.

8. It is permissible to create a class of embryos for research, some of whom will be killed, if killing some reduces the risk of all of dying—say, by providing stem cell therapies for the survivors. Creating embryos with a chance of being killed does not necessarily use the embryo as a means and instrumentalize them, if that killing reduces the overall risk of death (is “risk reductive”) for that population. See note 5, Savulescu 2002.

9. Harris J. The survival lottery. In: Harris J, ed. Bioethics. Oxford: Oxford University Press; 2001:300–15.

10. For example, the principle Purvu Urvu in Judaism is the principle of “go forth and multiply.”

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Cambridge Quarterly of Healthcare Ethics
  • ISSN: 0963-1801
  • EISSN: 1469-2147
  • URL: /core/journals/cambridge-quarterly-of-healthcare-ethics
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