(If the sperm contains 22 autosomes and 2 X chromosomes, the embryo will be a genetic female, and if it contains 22 autosomes and an X and a Y chromosome, the embryo will be a genetic male. (See Irving and Kischer, The Human Development Hoax: Time To Tell The Truth!, for extensive details and references.) He questions, in fact, the entire assumption and asks what neurological reasons there might be for concluding that an incapacity for consciousness becomes a capacity for consciousness once this point is passed. The products of gametogenesis are mature sex gametes with only 23 instead of 46 chromosomes. They each have only 23 chromosomes, not 46 chromosomes�the number of chromosomes necessary and characteristic for a single individual member of the human species. Fact 10: These claims are currently being made by bioethicists, research scientists, pharmaceutical companies, and other biotech research companies�even by some members of Congress. ... Spermatogenesis, the production of spermatozoa, continues from immediately after puberty until old age. (Alternative myths claim 14 days, or 3 weeks.). Life really is a form of chemistry, a particular form in which the chemicals can lead to their own reproduction. ); (2nd. Where did life originate? But quoting once again from O�Rahilly: "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 19th century as the so-called biogenetic law. Singer argues that the higher primates, e.g., dogs, pigs, apes, monkeys, are persons�but that some human beings, e.g., even normal human infants, and disabled human adults, are not persons. et al., The Rights and Wrongs of Abortions, (New Jersey: Princeton University Press, 1974), pp. If a single sperm or a single oocyte were implanted into a woman’s uterus, they would not grow; they would simply disintegrate. Our planet’s evolution started with the first organism ever to call our planet home. By puberty, only about 400,000 remain. Consequently, it is also scientifically incorrect to claim that only the inner cell layer constitutes the "embryo proper." The term �ovum� implies that polar body 2 has been given off, which event is usually delayed until the oocyte has been penetrated by a spermatozoon (i.e., has been fertilized). 18. This would include abortion, as well as the use of donated or "made-for-research" early human embryos in destructive experimental human embryo research (such as infertility research, cloning, stem cell research, the formation of chimeras, etc.). Ronan O�Rahilly and Fabiola Müller, Human Embryology & Teratology (New York: Wiley-Liss, 1994). Clifford Grobstein, Science and the Unborn: Choosing Human Futures (New York: Basic Books, Inc., 1988). Indeed, this definition does not directly address the central ethical question surrounding the embryo: What value ought society place on human life at the earliest stages of development? 19. After fertilization the single-cell human embryo doesn�t become another kind of thing. Thus the embryonic period also begins at fertilization, and ends by the end of the eighth week, when the fetal period begins. Ferment in U.S. Bioethics (Valley Forge, PA: Trinity Press International, 1994)�especially the "Preface" by Albert Jonsen. "31 (Emphasis added.). Myth 1: "Prolifers claim that the abortion of a human embryo or a human fetus is wrong because it destroys human life. Normally, the endometrium progresses to the secretory phase of the menstrual cycle as the zygote forms, undergoes cleavage, and enters the uterus. William J. Larsen, Human Embryology (New York: Churchill Livingstone, 1997), pp. The entire blastocyst�including both the inner and the outer cell layers�is the human embryo, the human being, the human individual. It was abandoned with great embarrassment after Plato�s time (even by Plato himself in his Parmenides! After puberty, under stimulation from the interstitial cells, spermatogonia proliferate ... and some become primary spermatocytes. (2008). See also, Bruce M. Carlson, Human Embryology and Developmental Biology (St. Louis, MO: Mosby, 1994), and Keith L. Moore and T.V.N. Organisms are “living beings.”  Therefore, another name for a human organism is a “human being”; an entity that is a complete human, rather than a part of a human. Myth 10: "Human embryo research, human cloning, stem cell research, and the formation of chimeras are acceptable kinds of research because until implantation or 14 days there is only a �pre-embryo�, a �potential� human embryo or human being present. Stem cell research obtains its "stem cells" by essentially exploding or otherwise destroying and killing a newly existing human blastocyst who is, scientifically, an existing human being. A human kidney or liver, a human skin cell, a sperm or an oocyte all possess human life, but they are not human beings�they are only parts of a human being. However, they too are "scientific" myths. Quoting from O�Rahilly again: "Partial duplication at an early stage and attempted duplication from 2 weeks onward (when bilateral symmetry has become manifest) would result in conjoined twins (e.g., �Siamese twins�). 19, 93. Fact 5: The immediate product of fertilization is genetically already a girl or a boy�determined by the kind of sperm that fertilizes the oocyte. Totipotency; What it is and what it is not. It is an attempt to deny the early human embryo its real identity as a human being and its real existence. Kennedy Institute of Ethics Journal 1991:1:1-15. Clearly, the zygote has entered into a new pattern of behavior, and therefore meets the second scientific criterion for being a new cell type. This would include such basic terms as: "gametogenesis," "oogenesis," "spermatogenesis," "fertilization," "zygote," "embryo," and "blastocyst." And even Karen Dawson acknowledges this as scientific fact in her article in Embryo Experimentation: "After the time of primitive streak formation, other events are possible 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. The zygote produces increasingly complex tissues, structures and organs that work together in a coordinated way. "10 (Emphasis added.). 9-13; A. Emery, Elements of Medical Genetics (New York: Churchill Livingstone, 1983), pp. The allantois forms a fibrous cord that is known as the urachus in the fetus and the median umbilical ligament in the adult. The scientific basis for distinguishing one cell type from another rests on two criteria:  differences in what something is made of (its molecular composition) and differences in how the cell behaves. "29 (Emphasis added.). And they are not individuals, i.e., members of the human species. What would this mean for the following list of adult human beings with diminished "rational attributes": e.g., the mentally ill, the mentally retarded, the depressed elderly, Alzheimer�s and Parkinson�s patients, drug addicts, alcoholics�and for those with diminished "sentience," e.g., the comatose, patients in a "vegetative state," paraplegics, and other paralyzed and disabled patients, diabetics or other patients with nerve or brain damage, etc.? Therefore, in considering the question of when a new human life begins, we must first address the more fundamental question of when a new cell, distinct from sperm and egg, comes into existence. "32 (Emphasis added.). This organized, coordinated behavior of the embryo is the defining characteristic of a human organism. Thus, the zygote acts immediately to oppose the function of the gametes from which it is derived; while the “goal” of both sperm and egg is to find each other and to fuse, the first act of the zygote is to prevent any further binding of sperm to the cell surface. Importantly, the cells, tissues and organs produced during development do not somehow “generate” the embryo (as if there were some unseen, mysterious “manufacturer” directing this process), they are produced by the embryo as it directs its own development to more mature stages of human life. "28 (Emphasis added.). The immediate product of human cloning would also be a human being�just as in human fertilization. That is, upon fertilization, parts of human beings have actually been transformed into something very different from what they were before; they have been changed into a single, whole human being. Moore and Persaud, p. 2; see also Jones, p. 177. ", Fact 13: Such claims are all pure mental speculation, the product of imposing philosophical (or theological) concepts on the scientific data, and have no scientific evidence to back them up. It�s an actual human being�with the potential to grow bigger and develop its capacities. )12 Finally, this new human being�the single-cell human zygote�is biologically an individual, a living organism�an individual member of the human species. They behave like cells, not like organisms. Clifford Grobstein, "External human fertilization," Scientific American 240:57-67. 44. What is being called a "fertilized egg" is not an egg of any sort; it is a human being. Even Daniel Callahan has admitted that the bioethics principles don�t work, in "Bioethics: Private choice and common good," in The Hastings Center Report (May/June 1994), pp. It takes place in the testis, which is also an endocrine gland, the interstitial cells of which secrete testosterone. Myth 13: "A human person begins with �brain birth,� the formation of the primitive nerve net, or the formation of the cortex�all physiological structures necessary to support thinking and feeling. Oddly, the influential book by Singer, Kuhse, Buckle, and Dawson, Embryo Experimentation,22 (which uses the term "pre-embryo," and which contains no scientific references for its "human embryology" chart or its list of "scientific" terms), along with the work of theologian McCormick and frog developmental biologist Grobstein, was used in the United States as the scientific basis for the 1994 National Institutes of Heath (NIH) Human Embryo Research Report.23 That Report concluded that the "preimplantation embryo" (they, too, originally used the term "pre-embryo") had only a "reduced moral status." But both private choices and public policies should incorporate sound and accurate science whenever possible. Some exchange occurs between these groups. This theory of recapitulation, however, has had a �regrettable influence in the progress of embryology� (citing de Beer). Postconception administration of hormones to prevent implantation of the blastocyst is sometimes used in cases of sexual assault or leakage of a condom, but this treatment is contraindicated for routine contraceptive use. I will not go into great detail here,39 but "personhood" begins when the human being begins�at fertilization. CLI is pleased to publish this slightly updated version of Dr. Maureen Condic’s fine essay on the science of new life. However, twinning is possible after 14 days, e.g., with fetus-in-fetu and Siamese twins. [1] Condic, M.L. Fire-starting is a key skill that different human groups could have passed along to each other—possibly even one that Neanderthals taught to some modern humans. McCormick often confuses these different periods in his writings. This situation weakens the possibility of seeing individuality as something irreversibly resolved by about 14 days after fertilization. Quoting Carlson again: "...[T]he sex of the future embryo is determined by the chromosomal complement of the spermatozoon. Oogonia (derived from primordial germ cells) multiply by mitosis and become primary oocytes. See also the writings of, e.g., H. Tristram Engelhardt, John Robertson (in legal writings), R.M.

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