Rather, it is the life of a distinct, unique, new individual who has never existed before in history and will never exist again. And the life that begins is not simply a continuation of the life of the sperm or egg cell. Human embryos begin development following the fusion of definitive male and female gametes during fertilization … This moment of zygote formation may be taken as the beginning or zero time point of embryonic development.Īs we can see, embryology textbooks are clear: life begins at fertilization. Larsen, Essentials of Human Embryology ), we read the following: 11):ĭevelopment begins with fertilization, the process by which the male gamete, the sperm, and the femal gamete, the oocyte, unite to give rise to a zygote.Īnd in another source (Ronan O’Rahilly and Fabiola Miller, Human Embryology and Teratology ):Īlthough 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. Sadler, Langman’s Medical Embryology (10 th edition, Philadelphia, PA: Lippincott Williams & Wilkins, 2006, p. This third embryology textbook is as clear as the first two – fertilization is the beginning of new life and the start of a new, distinct human organism.įrom T.W. O’Rahilly, Fabiola Muller, 5-55):įertilization is an important landmark because, under ordinary circumstances, a new, genetically distinct human organism is thereby formed Here is an example from another scientific work.įrom Human Embryology & Teratology (Ronan R. , formed by the union of an oocyte and a sperm, is the beginning of a new human being. Moore puts it even more plainly in Before We Are Born: Essentials of Embryology (7 th edition, Philadelphia, PA: Saunders, 2008, p. Few medical students can complete their careers without studying from his textbooks. He has written a number of definitive books on embryology, and his scientific knowledge and experience are vast and beyond reproach. The author of this scientific textbook, Keith L. “Oocyte” is another term for the egg cell, the cell released by woman’s ovary, which travels down the Fallopian tube and is fertilized by the male sperm. “Zygote” is a scientific term for the new life that is created when the sperm and the egg combine. This highly specialized, totipotent cell marks the beginning of each of us as a unique individual. Human development begins at fertilization, the process during which a male gamete … unites with a female gamete or oocyte … to form a single cell called a zygote. Moore’s The Developing Human: Clinically Oriented Embryology (7th edition, Philadelphia, PA: Saunders, 2003) states the following:Ī zygote is the beginning of a new human being. According to all the laws of nature, the preborn baby is human. No two dogs will ever conceive and give birth to a cat no fish egg will ever produce a snake. The offspring of two members of a species is always the same type of creature as the parents. It is indisputably human, as it has human DNA. Artistic metal representation of DNA double-helix structure.
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