"Only in the second quarter of the nineteenth century did biological research advance to the extent of understanding the actual mechanism of development. The nineteenth century saw a gradual but profoundly influential revolution in the
scientific understanding of the beginning of individual mammalian life. Although sperm had been discovered in 1677, the mammalian egg was not identified until 1827. The cell was first recognized as the structural unit of organisms in 1839, and the egg and sperm were recognized as cells in the next two decades. These developments were brought to the attention of the American state legislatures and public by those professionals most familiar with their unfolding import—physicians. It was the new research finding which persuaded doctors that the old 'quickening' distinction embodied in the common and some statutory law was unscientific and indefensible."
--
Victor G. Rosenblum
"Physicians have now arrived at the
unanimous opinion that the foetus in utero is alive from the very moment of conception. ... [T]he
willful killing of a human being at any stage of its existence is murder."
-- Dr. Horatio R. Storer, 1866
