"Maybe one way to think about it would be in the context of the historical development of germ theory. The problem of childbed fever was not significant until the development of a male-dominated medical establishment made possible the situation in which a professional might move from touching a corpse (for the purposes of study) to putting his unwashed hands up against, or into, a woman in labor."

Next Quote

One thing was absolutely certain—it was a given for Kazuo. Although he might not have particularlyrealized it, or more appropriately, perhaps because he was incapable of coming to such a realization, this was what it came down to: he, Kazuo Kiriyama, felt no emotion, no guilt, no sorrow, no pity, towards the four corpses, including Mitsuru's—and that ever since the day he was dropped into this world theway he was, he had never once felt a single emotion.

— Koushun Takami