Segregationist is a science-fiction short story by Isaac Asimov.
First published in Abbottempo, book 4, copyright Abbott Universal Ltd. "Segregationist" was later collected in 1969's Nightfall and Other Stories, 1982's The Complete Robot, and both of 1990's The Complete Stories and Robot Visions.
A surgeon struggles with the morals of replacing human organs with man-made devices. When does man stop being man? Where do we draw the line?