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Pregnancy Week by Week Development Week by Week Pregnancy The Multi-Dimensional Human Embryo The Endowment For Human Development: Prenatal Image Gallery University of New South Wales, Australia: Embryology The Virtual Human Embryo National Museum of Health and Medicine: Developmental Anatomy Gray's Anatomy Embryo characteristics and illustrations of embryo stages.

From the American College of Pediatricians: “When Human Life Begins:”

“The predominance of human biological research confirms that human life begins at conception – fertilization, the human being emerges as a whole, genetically distinct, individuated zygotic living human organism, a member of the species Homo sapiens, needing only the proper environment in order to grow and develop. The difference between the individual in its adult stage and in its zygotic stage is one of form, not nature. This statement focuses on the scientific evidence of when an individual human life begins.”

“The American College of Pediatricians concurs with the body of scientific evidence that corroborates that a unique human life starts when the sperm and egg bind to each other in a process of fusion of their respective membranes and a single hybrid cell called a zygote, or one-cell embryo, is created.”

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