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In 1993, investigators from George Washington University (GWU) Medical Center separated the cells of 17 human embryos and produced 48 embryos, an average of three embryos for each original. The method, variously called twinning, cloning, embryo splitting, and blastomere separation, demonstrated that human embryos could be split to create genetically identical entities during conception. When publicized, however, the experiment brought to mind a different view of cloning repeated since the beginning of the new reproductive technologies. In the early 1970s, when research on in vitro fertilization (IVF) was in its infancy, commentators worried that cloning–defined as the duplication of persons–would be next, leading to a scenario of “boys genetically exactly like the father, girls like the mother, or individuals like some true or false hero of art, science, or sports, or like some demagogue or some saint.”
1. Kolberg, R. Human embryo cloning reported. Science 1993;262:652–3, at p. 652.
2. Editorial, Stern, C. quoted in Genetic engineering in man: ethical considerations. Journal of the American Medical Association 1972;220:721.
3. Ferguson, MWJ. Contemporary and future possibilities for human embryonic manipulation. In: Dyson, A, Harris, J, Eds. Experiments on Embryos. London: Routledge, 1990:6–26.
4. Elmer-Dewitt, P. Cloning: where do we draw the line? Time 1993;11 8:64–70, at p. 67. I owe the distinction relating to the varying degrees of moral concern over body cell replication, adult replication, and twinning to Carson Holloway.
5. Brumby, M, Kasimba, P. When is cloning lawful? Journal of In Vitro Fertilization and Embryo Transfer 1987;4:198–204, at p. 198.
6. See note 5. Brumby, , Kasimba, . 1987;4:199, quoting from a medical dictionary.
7. See note 5. Brumby, , Kasimba, . 1987;4:199. Another level of cloning is the replication of genes, Or molecular cloning. Cohen, J, Tomkin, G. The science, fiction, and reality of embryo cloning. Kennedy Institute of Ethics Journal 1994;4:193–203, at p. 195.
8. Watson, JD. Moving toward the clonal man—is this what we want? Congressional Record 1971 04 29:12751–2, at p. 12751.
9. Voelker, R. A clone by any other name is still an ethical concern. Journal of the American Medical Association 1994;271:331–2, at p. 332; Warnock, M. A Question of Life: The Warnock Report on Human Fertilisation and Embryology. Oxford: Basil Blackwell, 1985; see note 2. Editorial. 1972;220:721; see note 8. Watson, . 1971;April 29:12751–2; see note 3. Ferguson, . 1990;6:23.
10. See note 3. Ferguson, . 1990;6:23.
11. See note 3. Ferguson, . 1990;6:22–4.
12. See note 9. Voelker, . 1994;271:332.
13. Kolata, G. Researcher clones embryos of human in fertility effort. New York Times 1993 10 24:1, 12.
14. Jones, HW Jr, Edwards, RG, Seidel, GE Jr. On attempts at cloning in the human. Fertility and Sterility 1994;61:423–6, at p. 424.
15. See note 13. Kolata, . 1993;October 24:1, 12.
16. See note 9. Warnock, . 1985:72.
17. Polyspermy is a condition in which more than one spermatozoan enters the egg and the fertilized egg has three or more pronuclei. It has been observed in 2–12% of embryos observed in IVF. Polyspermic embryos are not normally transferred to the uterus because of “potentially patholog ical consequences.” Angell, RR, Templeton, AA, Messinis, IE. Consequences of polyspermy in man. Cytogenetics Cell Genetics 1986;42:1–7, at p. 2.
18. Hall, JL, Engel, D, Gindoff PR, Mottle GL, Stillman RJ. Experimental cloning of human polyploid embryos using an artificial zone pellucida. Paper presented at the 1993 annual meeting of the American Fertility Society [Program supplement].
19. Robertson, JA. The question of human cloning. Hastings Center Report 1994;24:6–14, at p. 6.
20. Embryos split at the two cell stage cleaved to 32 cells at most, embryos split at the four cell stage cleaved to 16 cells at most, and embryos split at the eight cell stage cleaved to eight cells at most. See note 1. Kolberg, . 1993;262:652.
21. See note 18. Hall, et al. 1993.
22. See note 18. Hall, et al. 1993.
23. See note 14. Jones, et al. 1994;61:423; see note 4. Elmer-Dewitt, . 1993;November 8:67–8.
24. See note 14. Jones, et al. 1994;61:423.
25. Quoted in Fackelmann, KA. Cloning human embryos. Science News 1994;145:92–5, at p. 92.
26. See note 19. Robertson, . 1994;24:7.
27. See note 14. Jones, et al. 1994;61:423–6. See note 19. 1994;24:6–14. Robertson, uses the term “embryo splitting.” See note 7. 1994;4:196. Cohen and Tomkin note that blastomere separation occurs when a four or eight cell embryo is divided, and embryo splitting occurs when an embryo at the blastocyst stage is divided.
28. See note 1. Kolberg, . 1993;262:652.
29. See note 9. Voelker, . Stillman, RJ quoted in. 1994;271:331.
30. See note 18. Hall, et al. 1993.
31. See note 9. Voelker, . 1994;271:332.
32. See note 1. Kolberg, . 1993;262:653.
33. See note 14. Jones, et al. 1994;61:425.
34. See note 1. Kolberg, . 1993;262:652.
35. See note 9. Voelker, . 1994;271:332. See also National Institutes of Health. Final report of the human embryo research panel. 1994;September 27:70. The report concluded that blastomere separation for research purposes is “particularly sensitive” and warranted additional ethical review.
36. Norman Fost quoted in Kolata, C. Cloning human embryos: debate erupts over ethics. New York Times 1993;10 26:B7.
37. See note 19. Robertson, . 1994;24:12.
38. McCormick, RA. Blastomere separation: some concerns. Hastings Center Report 1994;24:14–16, at p. 15.
39. See note 38. McCormick, . 1994;24:15.
40. See note 1. Kolberg, . Quoted in. 1993;262:653.
41. See note 14. Jones, et al. 1994;61:426. As they put it, “A genetic Hitler born at another time and raised in a different environment could be a different person from the original.”
42. Kass, LR. Toward a More Natural Science: Biology and Human Affairs. New York: Free Press, 1985:66–9; see also note 36. Kolata, . 1993;10 26:B7, referring to Arthur Caplan.
43. See note 38. McCormick, . 1994;24:16.
44. See note 38. McCormick, , 1994;24:15.
45. See note 1. Kolberg, . 1993;262:653; see note 36. Kolata, . 1993;October 26:B7. Both refer to Arthur Caplan.
46. Jacoby, S. Entitled to the embryo? New York Times 1993 11 1:A19.
47. See note 36. Kolata, . 1993;October 26:87; see note 19. Robertson, . 1994;24:11.
48. See note 46. Jacoby, . 1993;November 1:A19.
49. Ramsey, P. Shall we “reproduce?” 1. The medical ethics of in vitro fertilization. Journal of the American Medical Association 1972;220:1346–50, at p. 1349.
50. See note 14. Jones, et al. 1994;61:425.
51. See note 19. Robertson, . 1994;24:7. See also National Institutes of Health. Final Report of the Human Embryo Research Panel. 1994;September 27:40. Still, if the twinned embryo is of high quality, transferring several opens the prospect for improved implantation rates.
52. See note 14. Jones, et al. 1994;61:425.
53. Callahan, D. What Kind of Life?: The Limits of Medical Progress. New York: Touchstone, 1990:160.
54. Jabbari, D. The role of law in reproductive medicine: a new approach. Journal of Medical Ethics 1990;16:35–40, at p. 37.
55. For a summary of European laws on assisted conception, see Morgan, D, Nielsen, L. Prisoners of progress or hostages to fortune? Journal of Law, Medicine & Ethics 1993;21:30–42.
56. Fletcher, JC. Germ-line gene therapy: the costs of premature ultimates. Politics and the Life Sciences 1994;13.
57. Royal Commission on New Reproductive Technologies. Update. 1993;December:5. See also Royal Commission on New Reproductive Technologies, Proceed With Care: Final Report of the Royal Commis sion on New Reproductive Technologies. Ottowa: Minister of Government Services Canada, 1993:636–7, 741, where cloning is defined as nuclear substitution.
58. See note 5. Brumby, , Kasimba, . 1987;4:198–204.
59. Law no. 68 of 12 June 1987 on artificial fertilization. International Digest of Health Legislation 1987; 38: 782–5.
60. Law no. 35/1988 of 22 November 1988 on assisted reproduction procedures. International Digest of Health Legislation 1989;90:82–93.
61. Human fertilisation and embryology act 1990. International Digest of Health Legislation 1991;42:69–85.
62. See note 9. Warnock, . 1985:73–4.
63. Ethics Advisory Board, Department of Health, Education, and Welfare. Appendix: HEW Support of Research Involving Human In Vitro Fertilization and Embryo Transfer. Washington DC: US Government Printing Office, 1979:173–5.
64. For public opinion polls regarding twinning, see By large margin, Americans oppose cloning of humans. New York Times 1993 11 1:A16; see note 4. Elmer-Dewitt, , 1993;November 8:64–70.
65. Davis v. Davis, 1992 Tenn. Lexis 400. Tenn. S. Ct. June 1, 1992; York v. Jones, 717 F. Supp. 421. E. D. Va 1989.
66. Kingdon, JW. Agendas, Alternatives, and Public Policies. Boston: Little, Brown and Company, 1984:99–100.
67. See, for example, Rifkin, J. Declaration of a Heretic. Boston: Routledge & Kegan Paul, 1985:53. “It is the first experiment that legitimizes the process.”
68. Wandersman, H, Hallman, WK. Are people acting irrationally? Understanding public concerns about environmental threats. American Psychologist 1993;48:68–86.
69. See note 19. Robertson, . 1994;24:6–14.
70. See note 53. Callahan, . 1990:160.
71. See note 42. Kass, . 1985:118.
72. Juengst, ET. The NIH “Points to consider” and the limits of human gene therapy. Human Gene Therapy 1990;1:425–33, at p. 431.
73. See note 38. McCormick, . 1994;24:16.
74. A detailed report on twinning from the National Advisory Board for Ethics in Reproduction (NABER) is published in an issue of the Kennedy Institute of Ethics Journal devoted to cloning. National Advisory Board on Ethics in Reproduction (NABER). Report on human cloning through embryo splitting: An amber light. Kennedy Institute of Ethics Journal 1994;4:251–82.
75. Ethics Committee, American Fertility Society. Ethical considerations of the new reproductive technologies. Fertility and Sterility 1990;53(Suppl. 2):1S–109S, at p. 63S.
76. For a criticism of the use of professional ethics committees, see Annas, GJ. Regulatory models for human embryo cloning: the free market, professional guidelines, and government restrictions. Kennedy Institute of Ethics Journal 1994;4:235–49, at pp. 241–2.
77. For example, delegates on the Council on Ethical and Judicial Affairs at the annual meeting of the American Medical Association supported “pre-embryo splitting.” American Medical News 1994;37:9.
78. See note 19. Robertson, . 1994;24:8.
79. See also Macklin, R. Splitting embryos on the slippery slope: ethics and public policy. Kennedy Institute of Ethics Journal 1994;4:209–25, at p. 224.
80. See note 14. Jones, et al. 1994;61:426.
81. Trounson, AL. Preimplantation diagnosis—Counting chickens before they hatch? Human Reproduction 1992;7:583–4; See note 2. Editorial. 1972;220:721.
82. See, for example, Evans, MI, Fletcher, JC, Zador, IE et al. Selection first trimester termination in octuplet and quadruplet pregnancies: clinical and ethical issues. Obstetrics and Gynecology 1988;71:289–96.
83. For a discussion of the symbolic importance of human embryos, see Robertson, JA. Embryo research. University of Western Ontario Law Review 1986;24:15–37.
84. In late 1994, President Clinton directed the National Institutes of Health to not fund projects in which human embryos are created for research purposes. Marshall, E. Clinton rules out some studies. Science 1994;266:1634–5.
85. See note 79. 1994;4:223. Macklin concludes that it “might be ethically prudent to limit the number of identical embryos that may be cloned from the original one.” See note 74. 1994;4:276. NABER recommends that only up to four embryos be produced from one embryo.
86. See note 74. 1994;4:276. NABER concluded it was not acceptable to freeze twinned embryos for the sole purpose of producing spaced twins. The group was divided on whether frozen twinned embryos should be transferred to the uterus if they were twinned to reduce the number of egg retrievals in in vitro fertilization and a birth had already occurred.
87. See, for example, Munson, R, Davis, LH. Germ-line gene therapy and the medical imperative. Kennedy Institute of Ethics Journal 1992;9:137–58.
88. Callahan, D. The Troubled Dream of Life: Living With Mortality. New York: Simon & Schuster, 1993:63,67.
89. See note 88. Callahan, . 1993:61.
90. Boone, CK. Bad axioms in genetic engineering. Hastings Center Report 1988;18:9–13, at p. 10.
91. See note 9. Voelker, . 1994;271:332.
92. Hanna, KE, Cook-Deegan, RM, Nishimi, RY. Bioethics and public policy: still seeking a forum. Politics and the Life Sciences 1994;13:102–5, at p. 102.
93. See note 14. Jones, et al. 1994;61:423.
94. See note 35. 1994;September 27:70. The Human Embryo Research Panel of the National Insti tutes of Health recommended that no funding should be given to twinning studies in which embryos are transferred. This is an indirect limit that withholds legitimacy from twinning while not outlawing it.
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