Additional Source #21 – Book
“A baby begins life as a single cell, smaller than the period at the end of this sentence, and would be only barely visible to the naked eye. This cell is created by the union of two parent cells: the female egg cell or ovum, and the male sperm cell.”21
21Sumner, W. Abortion and Moral Theory, Princeton, NJ: Princeton University Press, 1981, p. 10.