1 Ronan O'Rahilly and Fabiola Muller, Human Embryology & Teratology (New York: Wiley-Liss, 2001), p. ix. [Back]
2 See, e.g., Dianne N. Irving, "When does a human being begin? 'Scientific' myths and scientific facts" (International Journal of Sociology and Social Policy, 1999, 19:3/4:22-47). [Copy submitted to this Committee for the official record] [Back]
3 Wilhelm His, Anatomie menschlicher Embryonen (Leipzig: Vogel, 1880-1885); O"Rahilly and Muller 1994, p. 3; Keith L. Moore and T.V.N. Persaud, The Developing Human: Clinically Oriented Embryology (use 6th ed. only) (Philadelphia: W.B. Saunders Company, 1998), p. 12. [Back]
4 [emphases added]: "Although life is a continuous process, fertilization ... is a critical landmark because, under ordinary circumstances, a new, genetically distinct human organism is formed when the chromosomes of the male and female pronuclei blend in the oocyte... [The] coalescence of homologous chromosomes results in a one-cell embryo. ...The zygote is ... a unicellular embryo and is a highly specialized cell. ... [I]t is now accepted that the word embryo, as currently used in human embryology, means 'an unborn human in the first 8 weeks' from fertilization'. Embryonic life begins with the formation of a new embryonic genome (slightly prior to its activation)." [O'Rahilly and Muller, 2001, p. 87]
"Human pregnancy begins with the fusion of an egg and a sperm, ... Finally, the fertilized egg, now properly called an embryo, must make its way into the uterus ....". [Bruce Carlson, Human Embryology and Developmental Biology (St. Louis, MO: Mosby, 1994); also, Carlson, ibid., (2nd ed., 1999, p. 2]
"In this text, we begin our description of the developing human with the formation and differentiation of the male and female sex cells or gametes, which will unite at fertilization to initiate the embryonic development of a new individual. ... Fertilization takes place in the oviduct [not the uterus]... Embryonic development is considered to begin at this point. ... These pronuclei fuse with each other to produce the single, diploid, 2N nucleus of the fertilized zygote. This moment of zygote formation may be taken as the beginning or zero time point of embryonic development." [William Larson, Human Embryology (2nd ed.) (New York: Churchill Livingstone, 1997), pp. 1, 17]
"A zygote is the beginning of a new human being (i.e., an embryo); [Z]ygote: This highly specialized, totipotent cell marks the beginning of each of us as a unique individual.... Although fertilization may occur in other parts of the tube, it does not occur in the uterus. ... [T]he zygote, a unicellular embryo..." [Moore and Persaud 1998, pp. 2, 34] [Back]
5 [emphases added]: "A high percentage of abortuses (30-80%, depending on the study) are structurally abnormal, and it is maintained that all abortuses under 4 postovulatory weeks have abnormally formed embryonic tissue. Thus, spontaneous abortion greatly reduces the number of malformed fetuses born." [O'Rahilly and Muller 2001, pp. 92-93]
"Early spontaneous abortions occur for a variety of reasons, one being the presence of chromosomal abnormalities in the zygote. The early loss of embryos, once called pregnancy wastage, appears to represent a disposal of abnormal conceptuses that could not have developed normally, i.e., there is a natural screening of embryos." [Moore and Persaud 1998, p.p. 42-43] [Back]
6 See, e.g., G. Kollias, J. Hurst, E. deBoer, and F. Grosveld, "The Human beta-globulin gene contains a downstream developmental specific enhancer", Nucleic Acids Research 15(14) (July 1987), 5739-47; R. K. Humphries et al, "Transfer of human and murine globin-gene sequences into transgenic mice", American Journal of Human Genetics 37(2) (1985), 295-310; A. Schnieke et al, "Introduction of the human pro alpha 1 (I) collagen gene into pro alpha 1 (I) - deficient Mov-13 mouse cells leads to formation of functional mouse-human hybrid type I collagen", Proceedings of the National Academy of Science - USA 84(3) (Feb. 1987), pp. 764-8. [Back]
7 [emphases added]: "This process, which occurs about 4 days after fertilization, is called cavitation, and the fluid-filled space is known as the blastocoele. At this stage, the embryo as a whole is known as a blastocyst. (p. 38) ... At the blastocyst stage, the embryo consists of two types of cells: an outer superficial layer (the trophoblast) that surrounds a small inner group of cells called the inner cell mass. The appearance of these two cell types reflects major organizational changes that have occurred within the embryo and represents the specialization of the blastomeres into two distinct cell lineages. Cells of the inner cell mass give rise to the body of the embryo itself plus a number of extraembryonic structures." (Carlson 1999, pp. 39-40)
"'Primordium'" [e.g., "embryo proper"]: This term refers to the beginning or first discernible indication for the earliest stage of development of an organ or structure." (Moore and Persaud 1998, p. 3)
"Thus the germ layers should not be considered in rigid isolation one from another, and many interdependences, particularly what are termed epithelio-mesenchymal interactions, are important in development. (p. 10); ... The developmental adnexa, commonly but inaccurately referred to as the "fetal membranes", include the trophoblast, amnion, chorion, umbilical vesicle (yolk sac), allantoic diverticulum, placenta and umbilical cord. These temporary structures are interposed between the embryo/fetus and the maternal tissues. ... The adnexa are programmed to mature fast, to age more rapidly, and to die sooner than the embryonic/fetal body. Nevertheless they are genetically a part of the individual and are composed of the same germ layers." (O'Rahilly and Muller 1994, p. 51). [Back]
8 "The appearance of the blastocyst demonstrates the differentiation into (1) trophoblast (or trophectoderm), the peripherally situated cells and (under the influence of E-cadherin) in first epithelium formed, and (2) embryonic cells proper. The latter, at first few in number, form the inner cell mass (ICM). The trophoblast at the future site of attachment is sometimes termed polar, the remainder being called mural. The cells of the ICM (inner cell mass) are considered to be totipotent initially." (emphases added) [O'Rahilly and Muller 2001, p. 39] [Back]
9 "[O]ther events are possible after this time [segmentation -- 14 days] which indicate that the notion of "irreversible individuality" may need some review if it is to be considered as an important criterion in human life coming "to be the individual human being it is ever thereafter to be". There are two conditions which raise questions about the adequacy of this notion: conjoined twins, sometimes known as Siamese twins, and fetus-in-fetu. ... Although conjoined twins and fetus-in-fetu have rarely been documented, the possibility of their occurring raises several points related to the notion of irreversible individuality. Conjoined twins arise from the twinning process occurring after the primitive streak has begun to form, that is, beyond 14 days after fertilization, or, in terms of the argument from segmentation, beyond the time at which irreversible individuality is said to exist. ... Similar reasoning leads to the same confusion in the case of fetus-in-fetu. ... One case recorded and studied in detail showed that the engulfed twin had developed to the equivalent of four months gestation and consisted of brain, bones, nerve tissue, muscle and some rudimentary organs. Microscopic study showed that engulfment had occurred at about four weeks after fertilization, in terms of the argument for segmentation long after the time when it is claimed that individuality is resolved." [Her reference is: Yasuda, Y., Mitomori, T., Matsurra, A. and Tanimura, T., "Fetus-in-fetu: report of a case", Teratology 31 (1985), 337-41.] [Karen Dawson, "Segmentation and moral status", in Peter Singer, Helga Kuhse, Stephen Buckle, Karen Dawson, and Pascal Kasimba, Embryo Experimentation (New York: Cambridge University Press, 1990), pp. 57-59].
See also: "MZ [monozygotic] twinning usually begins in the blastocyst stage, around the end of the first week (before formation of the germ disc starting at 8 days).... Uncommonly, early separation of embryonic blastomeres, (e.g., during the 2 - 8 cell stages) results in MZ twins with two amnions, two chorions, and two placentas that may or may not be fused. (p. 159); ... About 35% of MZ twins result from early separation of the embryonic blastomeres; i.e., during the first 3 days of development. The other 65% of MZ twins originate at the end of the first week of development; i.e., right after the blastocyst has formed [5-7 days]. Late division of early embryonic cells, such as division of the embryonic disc during the second week, results in MZ twins that are in one amniotic sac and one chorionic sac." (p. 159); ... If the embryonic disk does not divide completely, or adjacent embryonic discs fuse, various types of conjoined MZ twins may form. ... the incidence of conjoined (Siamese) twins is 1 in 50,000- 100,000 births." (emphases added) [Moore and Persaud 1998, p. 161].
"Partial duplication at an early stage and attempted duplication from 2 weeks onward (when bilateral symmetry has become manifest) would result in conjoined twins." (p. 30); ... Once the primitive streak has appeared at about 13 days, splitting that involves the longitudinal axis of the embryo would be incomplete and would result in conjoined twins." [O'Rahilly and Muller 1994, p. 30]. ... Similarly, after the appearance of the primitive streak and notochordal process, any attempt at longitudinal division would be incomplete and would result in conjoined [Siamese] twins." (emphases added) [ibid, 2001, p. 55] [Back]
10 "Egg"; best confined to the hen and to cuisine; use "oocyte". "Ovum"; does not exist in human; use "oocyte", "ootid", "embryo". [O'Rahilly and Muller 2001, p. 12] [Back]
11 "The term 'pre-embryo' is not used here for the following reasons: (1) it is ill-defined because it is said to end with the appearance of the primitive streak or to include neurulation; (2) it is inaccurate because purely embryonic cells can already be distinguished after a few days, as can also the embryonic (not pre-embryonic!) disc; (3) it is unjustified because the accepted meaning of the word embryo includes all of the first 8 weeks; (4) it is equivocal because it may convey the erroneous idea that a new human organism is formed at only some considerable time after fertilization; and (5) it was introduced in 1986 'largely for public policy reasons' (Biggers)." ... Just as postnatal age begins at birth, prenatal age begins at fertilization." [O'Rahilly and Muller 2001, p. 88] ... "Undesirable terms in Human Embryology": "Pre-embryo"; ill-defined and inaccurate; use "embryo". (emphases added) [O'Rahilly and Muller 2001, p. 12]. [Back]
12 "Recapitulation, the So-Called Biogenetic Law. The theory that successive stages of individual development (ontogeny) correspond with ("recapitulate") successive adult ancestors in the line of evolutionary descent (phylogeny) became popular in the nineteenth century as the so-called biogenetic law. This theory of recapitulation, however, has had a "regrettable influence on the progress of embryology" (G. de Beer). ... According to the "laws" of von Baer, general characters (e.g., brain, notochord) appear in development earlier than special characters (e.g., limbs, hair). Furthermore, during its development an animal departs more and more from the form of other animals. Indeed, the early stages in the development of an animal are not like the adult stages of other forms but resemble only the early stages of those animals. The pharyngeal clefts of vertebrate embryos, for example, are neither gills nor slits. Although a fish elaborates this region into gill slits, in reptiles, birds, and mammals it is converted into such structures as the tonsils and the thymus." (emphases added) [O'Rahilly and Muller 2001, p. 16]. [Back]
13 "The embryo enters the uterine cavity after about half a week ... Each cell (blastomere) is considered to be still totipotent (capable, on isolation, of forming a complete embryo), and separation of these early cells is believed to account for one-third of cases of monozygotic twinning." (emphases added) [O'Rahilly and Muller, p. 37] " ... Some types of twinning represent a natural experiment that demonstrates the highly regulative nature of early human embryos, ..." (p. 48); "... Monozygotic twins and some triplets, on the other hand, are the product of one fertilized egg. They arise by the subdivision and splitting of a single embryo. Although monozygotic twins could ... arise by the splitting of a two-cell embryo, it is commonly accepted that most arise by the subdivision of the inner cell mass in a blastocyst. Because the majority of monozygotic twins are perfectly normal, the early human embryo can obviously be subdivided and each component regulated to form a normal embryo." (p. 49) (emphases added) [Carlson 1999] "If the splitting occurred during cleavage -- for example, if the two blastomeres produced by the first cleavage division become separated -- the monozygotic twin blastomeres will implant separately, like dizygotic twin blastomeres, and will not share fetal membranes. Alternatively, if the twins are formed by splitting of the inner cell mass within the blastocyst, they will occupy the same chorion but will be enclosed by separate amnions and will use separate placentae, each placenta developing around the connecting stalk of its respective embryo. Finally, if the twins are formed by splitting of a bilaminar germ disc, they will occupy the same amnion." (p. 325) [Larsen 1998] "MZ [monozygotic] twinning usually begins in the blastocyst stage, around the end of the first week (before formation of the germ disc starting at 8 days).... Uncommonly, early separation of embryonic blastomeres, (e.g., during the 2 - 8 cell stages) results in MZ twins with two amnions, two chorions, and two placentas that may or may not be fused. (p. 159); ... About 35% of MZ twins result from early separation of the embryonic blastomeres; i.e., during the first 3 days of development. The other 65% of MZ twins originate at the end of the first week of development; i.e., right after the blastocyst has formed [5-7 days]. [Moore and Persaud 1998, p. 161]. [Back]
14 "The term 'clones' indicates genetic identity and so can describe genetically identical molecules (DNA clones), genetically identical cells or genetically identical organisms. Animal clones occur naturally as a result of sexual reproduction. For example, genetically identical twins are clones who happened to have received exactly the same set of genetic instructions from two donor individuals, a mother and a father. A form of animal cloning can also occur as a result of artificial manipulation to bring about a type of asexual reproduction. The genetic manipulation in this case uses nuclear transfer technology: a nucleus is removed from a donor cell then transplanted into an oocyte whose own nucleus has previously been removed. The resulting 'renucleated' oocyte can give rise to an individual who will carry the nuclear genome of only one donor individual, unlike genetically identical twins. The individual providing the donor nucleus and the individual that develops from the 'renucleated' oocyte are usually described as "clones", but it should be noted that they share only the same nuclear DNA; they do not share the same mitochondrial DNA, unlike genetically identical twins." (emphases added) [Tom Strachan and Andrew P. Read, Human Molecular Genetics 2 (New York: John Wiley & Sons, Inc, 1999), pp. 508-509]. [Back]
15 "Cells differentiate by the switching off of large portions of their genome." [O'Rahilly and Mueller 2001, p. 39]. "Gene expression is associated with demethylation. Methylation of DNA is one of the parameters that controls transcription. This is one of several regulatory events that influence the activity of a promoter; like the other regulatory events, typically this will apply to both copies of the gene." [Benjamin Lewin, Genes VII (New York: Oxford University Press, Inc., 2000), p. 678; also p. 603]. "Gene regulation as the primary function for DNA methylation: DNA methylation in vertebrates has been viewed as a mechanism for silencing transcription and may constitute a default position." [Strachan and Read, pp. 193 ff] [Back]
16 "The expression of genes is determined by a regulatory network that probably takes the form of a cascade. Expression of the first set of genes at the start of embryonic development leads to expression of the genes involved in the next stage of development, which in turn leads to a further stage, and so on until all the tissues of the adult are functioning." [Lewin, p. 63; also pp. 914, 950]. [Back]
17 "A variety of early experiments in mice were also unsuccessful before the landmark study of Wilmut et al (1997) reported successful cloning of an adult sheep. For the first time, an adult nucleus had been reprogrammed to become totipotent once more, just like the genetic material in the fertilized oocyte from which the donor cell had ultimately developed. ... Successful cloning of adult animals has forced us to accept that genome modifications once considered irreversible can be reversed and that the genomes of adult cells can be reprogrammed by factors in the oocyte to make them totipotent once again. ... Other more recent studies are now forcing us to reconsider the potency of other cells. ... [A]nd so the developmental potential of stem cells is not restricted to the differentiated elements of the tissue in which they reside (Bjornson et al, 1999)." (emphases added) [Tom Strachan & Andrew P. Read, Human Molecular Genetics 2 (New York: Wiley-Liss, 1999), p. 509] [Back]
18 "Early mammalian embryogenesis is considered to be a highly regulative process. Regulation is the ability of an embryo or an organ primordium to produce a normal structure if parts have been removed or added. At the cellular level, it means that the fates of cells in a regulative system are not irretrievably fixed and that the cells can still respond to environmental cues." (pp. 44-49). ... Blastomere removal and addition experiments have convincingly demonstrated the regulative nature (i.e., the strong tendency for the system to be restored to wholeness) of early mammalian embryos. Such knowledge is important in understanding the reason exposure of early human embryos to unfavorable environmental influences typically results in either death or a normal embryo." (p. 46) [Carlson 1999] [Back]
19 See note 13, supra; also, (emphases added): "Another means of demonstrating the regulative properties of early mammalian embryos is to dissociate mouse embryos into separate blastomeres and then to combine the blastomeres of two or three embryos. The combined blastomeres soon aggregate and reorganize to become a single large embryo, which then goes on to become a normal-appearing tetraparental or hexaparental mouse. By various techniques of making chimeric embryos, it is even possible to combine blastomeres to produce interspecies chimeras (e.g., a sheep-goat)." (p. 45); "... The relationship between the position of the blastomeres and their ultimate developmental fate was incorporated into the inside-outside hypothesis. The outer blastomeres ultimately differentiate into the trophoblast, whereas the inner blastomeres form the inner cell mass, from which the body of the embryo arises. Although this hypothesis has been supported by a variety of experiments, the mechanisms by which the blastomeres recognize their positions and then differentiate accordingly have remained elusive and are still little understood. If marked blastomeres from disaggregated embryos are placed on the outside of another early embryo, they typically contribute to the formation of the trophoblast. Conversely, if the same marked cells are introduced into the interior of the host embryo, they participate in formation of the inner cell mass. Outer cells in the early mammalian embryo are linked by tight and gap junctions ... Experiments of this type demonstrate that the developmental potential or potency (the types of cells that a precursor cell can form) of many cells is greater than their normal developmental fate (the types of cells that a precursor cell normally forms)." (p. 45); "... Classic strategies for investigating developmental properties of embryos are (1) removing a part and determining the way the remainder of the embryo compensates for the loss (such experiments are called deletion experiments) and (2) adding a part and determining the way the embryo integrates the added material into its overall body plan (such experiments are called addition experiments). Although some deletion experiments have been done, the strategy of addition experiments has proved to be most fruitful in elucidating mechanisms controlling mammalian embryogenesis." (p. 46). [Carlson 1999] "Of the experimental techniques used to demonstrate regulative properties of early embryos, the simplest is to separate the blastomeres of early cleavage-stage embryos and determine whether each one can give rise to an entire embryo. This method has been used to demonstrate that single blastomeres, from two- and sometimes four-cell embryos can form normal embryos, ..." (emphases added) [Carlson 1999, p. 44]
See also the use of the cloning technique of twinning by "blastomere separation" and "blastocyst splitting" proposed by many IVF researchers -- what they refer to as "embryo multiplication":
Professor Dr. Mithhat Erenus, "Embryo Multiplication": "In such cases, patients may benefit from embryo multiplication, as discussed in the study by Massey and co-workers. ... Since each early embryonic cell is totipotent (i.e., has the ability to develop and produce a normal adult), embryo multiplication is technically possible. Experiments in this area began as early as 1894, when the totipotency of echinoderm embryonic cells was reported ... In humans, removal of less than half of the cells from an embryo have been documented. No adverse effects were reported when an eighth to a quarter of the blastomeres were removed from an embryo on day 3 after insemination. ... Further evidence supporting the viability and growth of partial human embryos is provided by cryopreservation. After thawing four-cell embryos, some cells may not survive, leaving one-, two-, or three-cell embryos. These partial embryos survive and go to term, but at a lower rate than whole embryos. ... Based on the results observed in lower order mammals, the critical period of development to ensure success in separating human blastomeres should be at the time of embryonic gene expression, which is reported in humans to be between the four- and eight-cell stages. .... The second potential method of embryo multiplication is blastocyst splitting. ... Embryo multiplication by nuclear transfer has been used in experimental cattle breeding programs. ... IVF clinics routinely replace multiple (three to four) embryos into the uterus to increase the chances of a successful pregnancy. For couples who have less than three quality embryos for transfer, blastomere separation could be of benefit." [ http://www.hekim.net/~erenus/20002001/asistedreproduction/micromanipulation/embryo_multiplication.htm ].
See also, "New Ways to Produce Identical Twins -- A Continuing Controversy": "Identical twins occur naturally approximately 3.5 times out of every 1000 human births. And, to date, scientists still don't know why and can't predict that they will, in any given birth, occur. However, in the last half of this century, and indeed, in the past ten to fifteen years, scientific advances have impacted on twins and other multiples and their families in numerous ways. ... Now, a new method of actually producing identical twins looms near. Called "blastomere separation" (the separation of a two- to eight-cell blastomere into two identical demi-embryos), it is potentially one method of helping infertile couples have children through in vitro fertilization (IVF). ... The following is excerpted from the medical journal Assisted Reproduction Reviews, May 1994. Dr. Joe B. Massey, who heads an in vitro clinic in Atlanta. Dr. Massey reviews the advances in blastomere separation and discusses the potential indications, benefits, limitations, and ethics of using this method to produce monozygotic twin embryos for IVF patients. The Twins Foundation, by presenting Dr. Massey's material for your information neither advocates nor rejects any such procedures: 'Embryo Multiplication by Blastomere Separation-One Doctor's Proposal [Massey]: In spite of many advances in human in vitro fertilization (IVF), there are still many problems. While leading clinics now have success rates of about 30%, many other clinics lag behind. Still, the number of couples undergoing IVF continues to increase despite high costs.' ... According to Dr. Massey, 'Observations on the potential impact of removing less than half of the cells from the human embryo have been well documented in pre-clinical embryo biopsy studies.' (For more on this story see Research Update Vol. 9, No. 1, 1994)." [on THE TWINS FOUNDATION ( http://twinsfoundation.com/ru-v9n1-1994.htm )].
See also "embryo self-selection": "The ability to grow embryos for five days to the blastocyst stage of development in the laboratory, rather than the traditional three days, allows clinicians to determine with greater certainty which embryos are really the "best" in terms of their potential for implantation. Consequently, blastocyst culture makes it possible to select the best one or two blastocysts vs. three or four early embryos to transfer back to the mother. Fertility centers like Shady Grove constantly strive to improve IVF success rates through the steady refinements of clinical and laboratory techniques. Clinical blastocyst culture and transfer is the next important step in that evolution,' explains Robert Stillman, MD: 'After five days of growth, the cells of the embryo should have divided many times over, and have begun to differentiate by function. The embryos that survive to this stage of development are usually strong, healthy, and robust. ... Simply put, this self selection can be viewed as 'survival of the fittest. ... Which ones to transfer? Which ones are really the "best'? Two additional days in the blastocyst culture medium allows the natural winnowing process to continue. Thus, after 5 days of growth in the laboratory, only 2 or 3 of the original ten embryos may remain viable. We now know the best embryos to transfer. ... In thinking of the example above, patients who have fewer oocytes retrieved, fewer fertilized or fewer dividing embryos by day three in culture have no advantage using blastocyst culture, since little is to be gained in further embryo 'self selection'. Dr. Stillman emphasizes." [on FERTILITY NETWORK ( http://fertilitynetwork.com/articles/articles-blastocyst.htm )]
ETHICS COMMITTEE OF THE AMERICAN SOCIETY FOR REPRODUCTIVE MEDICINE, "'Ethical Considerations of Assisted Reproductive Technologies': Originally published as a supplement to the ASRM medical journal (Fertility and Sterility 1994;62:Suppl 1), Ethical Considerations for Assisted Reproductive Technologies covers the American Society for Reproductive Medicine's position on several aspects of reproductive medicine, including: ... the moral and legal status of the preembryo, ... the use of donor sperm, donor oocytes and donor preembryos, ... the cryopreservation of oocytes and preembryos, micro techniques such as: zona drilling, microinjection, blastomere separation (cloning), and assisted hatching." [ http://www.asrm.com/media/ethics/ethics94.html ].
See also: "Because early embryonic cells are totipotent, the possibility of splitting or separating the blastomeres of early preimplantation embryos to increase the number of embryos that are available for IVF treatment of infertility is being discussed. Because embryo splitting could lead to two or more embryos with the same genome, the term "cloning" has been used to describe this practice. ... Splitting one embryo into two or more embryos could serve the needs of infertile couples in several ways. For couples who can produce only one or two embryos, splitting embryos could increase the number of embryos available for transfer in a single IVF cycle. Because the IVF pregnancy rate increases with the number of embryos transferred, it is thought that embryo splitting when only one or two embryos are produced may result in a pregnancy that would not otherwise have occurred. For couples who produce more than enough embryos for one cycle of transfer, splitting one or more embryos may provide sufficient embryos for subsequent transfers without having to go through another retrieval cycle, thus lessening the physical burdens and costs of IVF treatment for infertility. In addition, this technique may have application in preimplantation genetic diagnosis. ... Whereas these ethical concerns raise important issues, neither alone nor together do they offer sufficient reasons for not proceeding with research into embryo splitting and blastomere separation. ... In sum, since embryo splitting has the potential to improve the efficacy of IVF treatments for infertility, research to investigate the technique is ethically acceptable. Persons asked to donate gametes or embryos for such research should be fully informed that research in embryo splitting is intended or planned as a result of their donation. The fears of possible future abuses of the technique are not sufficient to stop valid research in use of embryo splitting as a treatment for infertility. This statement was developed by the American Society for Reproductive Medicine's Ethics Committee and accepted by the Board of Directors on December 8, 1995. [on AMERICAN SOCIETY OF REPRODUCTIVE MEDICINE ( http://www.asrm.com/media/ethics/embsplit.html )]. [Back]
20 "Like all normal somatic (i.e., non-germ cells), the primordial germ cells contain 23 pairs of chromosomes, or a total of 46 [and thus could be cloned by nuclear transplant]" [Larsen 1998, p. 4]. "A subset of the diploid body cells constitute the germ line. These give rise to specialized diploid cells in the ovary and testis that can divide by meiosis to produce haploid gametes." [Strachan and Read 1999, p. 28]. "Meiosis is a special type of cell division that involves two meiotic cell divisions; it takes place in germ cells only. Diploid germ cells give rise to haploid gametes (sperms and oocytes)." [Moore and Persaud 1998, p. 18]. "In a mitotic division, each germ cell produces two diploid progeny that are genetically equal." [Carlson 1999, p. 2]. "Future somatic cells thereby lose their totipotency and are liable to senescence, whereas germ cells regain their totipotency after meiosis and fertilization [and therefore could undergo regulation to produce new embryos]." [O'Rahilly and Muller 2001, p. 39]. "Early primordial germ cells are spared; their genomic DNA remains very largely unmethylated until after gonadal differentiation and as the germ cells develop whereupon widespread de novo methylation occurs." (emphases added) [Tom Strachan and Andrew Read, Human Molecular Genetics 2 (2nd ed.) (New York: Wiley-Liss, 1999), p. 191] [Back]
21 "The term 'clones' indicates genetic identity and so can describe genetically identical molecules (DNA clones), genetically identical cells or genetically identical organisms. Animal clones occur naturally as a result of sexual reproduction. For example, genetically identical twins are clones who happened to have received exactly the same set of genetic instructions from two donor individuals, a mother and a father. A form of animal cloning can also occur as a result of artificial manipulation to bring about a type of asexual reproduction. The genetic manipulation in this case uses nuclear transfer technology: a nucleus is removed from a donor cell then transplanted into an oocyte whose own nucleus has previously been removed. The resulting 'renucleated' oocyte can give rise to an individual who will carry the nuclear genome of only one donor individual, unlike genetically identical twins. The individual providing the donor nucleus and the individual that develops from the 'renucleated' oocyte are usually described as "clones", but it should be noted that they share only the same nuclear DNA; they do not share the same mitochondrial DNA, unlike genetically identical twins." (emphases added) [Strachan and Read 1999, pp. 508-509] [Back]
22 See especially, Tom Strachan and Andrew P. Read, Human Molecular Genetics (New York: Wiley-Liss, 1999), pp. 539-541: "From the ethical point of view, an important consideration is to what extent technologies developed in an attempt to engineer the human germline could subsequently be used not to treat disease but in genetic enhancement. There are powerful arguments as to why germline gene therapy is pointless. There are serious concerns, therefore, that a hidden motive for germline gene therapy is to enable research to be done on germline manipulation with the ultimate aim of germline-based genetic enhancement. The latter could result in positive eugenics programs, whereby planned genetic modification of the germline could involve artificial selection for genes that are thought to confer advantageous traits. ... The implications of human genetic enhancement are enormous. Future technological developments may make it possible to make very large alterations to the human germline by, for example, adding many novel genes using human artificial chromosomes (Grimes and Cooke, 1998). Some people consider that this could advance human evolution, possibly paving the way for a new species, homo sapientissimus. To have any impact on evolution, however, genetic enhancement would need to be operated on an unfeasibly large scale (Gordon, 1999). ... Even if positive eugenics programs were judged to be acceptable in principle and genetic enhancement were to be practiced on a small scale, there are extremely serious ethical concerns. Who decides what traits are advantageous? Who decides how such programs will be carried out? Will the people selected to have their germlines altered be chosen on their ability to pay? How can we ensure that it will not lead to discrimination against individuals? Previous negative eugenics programs serve as a cautionary reminder. In the recent past, for example, there have been horrifying eugenics programs in Nazi Germany, and also in many states of the USA where compulsory sterilization of individuals adjudged to be feeble-minded was practiced well into the present century." (emphases added) [Back]
23 Peter Singer, "Taking life: abortion", in Practical Ethics (London: Cambridge University Press, 1981), p. 118. See also: Helga Kuhse and Peter Singer, "For sometimes letting - and helping - die", Law, Medicine and Health Care 3(4), 1986: pp. 149-153; also Kuhse and Singer, Should the Baby Live? The Problem of Handicapped Infants (Oxford: Oxford University Press, 1985), p. 138; Peter Singer and Helga Kuhse, "The ethics of embryo research", Law, Medicine and Health Care 14(13-14), 1987. For one reaction, see Gavin J. Fairbairn, "Kuhse, Singer and slippery slopes", Journal of Medical Ethics 14 (1988), p. 134. [Back]
24 See Dianne N. Irving, "Science, philosophy, theology - and altruism: the chorismos and the zygon", in Hans May, Meinfried Striegnitz, Philip Hefner (eds.), Loccumer Protokolle (Rehburg-Loccum: Evangelische Akademie Loccum, 1996); Etienne Gilson, Being and Some Philosophers (Toronto: Pontifical Institute of Mediaeval Studies, 1949); Frederick Copleston, A History of Philosophy (New York: Image Books, 1962); Leonard J. Eslick, "The material substrate in Plato", in Ernan McMullin (ed.), The Concept of Matter in Greek and Medieval Philosophy (Indiana: University of Notre Dame Press, 1963); Frederick Wilhelmsen, Man's Knowledge of Reality (New Jersey: Prentice-Hall, Inc., 1956), esp. Chaps. 2 and 3. For an excellent explanation of the difference between basing "personhood" on just functionality vs. the kind of nature possessed, see Kevin Doran, "Person -- a key concept for ethics", Linacre Quarterly 56 (4), 1989, 39. [Back]
25 See D. N. Irving, Philosophical and Scientific Analysis of the Nature of the Early Human Embryo (doctoral dissertation) (Washington, D.C.: Georgetown University, 1991). A short version of the dissertation can be found in D. N. Irving, "Philosophical and scientific expertise: An evaluation of the arguments on 'personhood'" (Linacre Quarterly, Feb. 1993, 60:1:18-46). [Copy submitted to this Committee for the official record.] [Back]
26 Peter Singer, "Heavy Petting" [http://www.nerve.com/Opinions/Singer/heavyPetting]. [Back]
27 Richard G. Frey, The ethics of the search for benefits: Animal experimentation in medicine", in Raanan Gillon (ed.), Principles of Health Care Ethics (New York: John Wiley & Sons, 1994), pp. 1067-1075. [Back]
28 The National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research, The Belmont Report (Washington, D.C: U.S. Department of Health, Education, and Welfare, 1978); The National Research Act, Public Law 93-348, 93rd Congress, 2nd session (July 12, 1974); 88 STAT 342. See also, Albert R. Jonsen, The Birth of Bioethics (New York: Oxford University Press, 1998); also, David J. Rothman, Strangers at the Bedside: A History of How Law and Bioethics Transformed Medical Decision Making (New York: BasicBooks; a subsidiary of Perseus Books, L.L.C., 1991); D. N. Irving, "What is 'bioethics'?", UFL Proceedings of the Conference 2000, in Joseph W. Koterski (ed.), Life and Learning X: Proceedings of the Tenth University Faculty For Life Conference (Washington, D.C.: University Faculty For Life, 2002), pp. 1-84. [Copy submitted to this Committee for the official record.] This writer has one of her two doctoral concentrations in bioethics from the Kennedy Institute of Ethics, Georgetown University (1991). See also my doctoral dissertation, note 25, supra. [Back]
29 See, e.g., E.g., Tom Beauchamp and James Childress, Principles of Biomedical Ethics (1st ed.) (New York: Oxford University Press, 1979), pp. 45-47; Tom Beauchamp and LeRoy Walters (eds.), Contemporary Issues in Bioethics (2nd ed.) (Belmont, CA: Wadsworth Publishing Company, Inc., 1982), p.26; Tom Beauchamp, Philosophical Ethics (New York: McGraw-Hill Book Company, 1982, pp. 124-128, 141, 188-190; Tom Beauchamp; and Laurence B. McCullough, Medical Ethics: The Moral Responsibilities of Physicians (New Jersey: Prentice-Hall, Inc., 1984), pp. 13-16, 21-22, 39-40, 46, 48, 133-35, 162-64. [Back]
30 E.g., The Hastings Center's Daniel Callahan conceded in the 25th anniversary issue of The Hastings Center Report celebrating the "birth of bioethics", that the principles of bioethics simply had not worked. But not to worry, he said, we might try communitarianism now: "The range of questions that a communitarian bioethics would pose could keep the field of bioethics well and richly occupied for at least another 25 years"! (emphases added) [Daniel Callahan, "Bioethics: Private Choice and Common Good", Hastings Center Report (May-June 1994), 24:3:31]. [Back]
31 "A fairly widespread perception exists, both within and without the bioethics community, that the prevailing U.S. approach to the ethical problems raised by modern medicine is ailing. Principlism [bioethics] is the patient. The diagnosis is complex, but many believe that the patient is seriously, if not terminally, ill. The prognosis is uncertain. Some observers have proposed a variety of therapies to restore it to health. Others expect its demise and propose ways to go on without it.", Albert Jonsen, in Edwin DuBose, Ronald Hamel and Laurence O'Connell (eds.), A Matter of Principles?: Ferment in U.S. Bioethics (Valley Forge, PA: Trinity Press International, 1994), p.1. See also: Gilbert C. Meilaender, Body Soul, and Bioethics (Notre Dame, IN: University of Notre Dame Press, 1995), p. x; Raanan Gillon (ed.), Principles of Health Care Ethics (New York: John Wiley & Sons, 1994) -- in which 99 scholars from around the world jump into the fray over bioethics -- by far the majority of them arguing against bioethics "principlism"; Renee Fox, "The Evolution of American Bioethics: A Sociological Perspective," in George Weisz (ed.), Social Sciences Perspective on Medical Ethics (Philadelphia: University of Pennsylvania Press, 1990), pp. 201-220. Renee Fox and Judith Swazey, "Medical Morality is Not Bioethics -- Medical Ethics in China and the United States," Perspectives in Biology and Medicine 27 (1984):336-360, in Jonsen p. 358; Renee C. Fox and Judith P. Swazey, "Leaving the Field", Hastings Center Report (September-October 1992), 22:5:9-15. [Back]
32 Original Hastings Center scholar Robert Morison, in Jonsen (pp. 109-110). As Jonsen noted, "Morison's letter was a sobering reminder of the anomalous role of an 'ethics commission' in a pluralistic, secular society." [Back]
1, 2,