Scientific Source #57 – Medical Textbook
“Human development begins at fertilization when a male gamete or sperm unites with a female gamete or oocyte to form a single cell, a zygote. This highly specialized, totipotent cell marks the beginning of each of us as a unique individual.”57
57Moore, K.L., The Developing Human: Clinically Oriented Embryology, 8th ed., Philadelphia: Saunders, 2007. p. 15.