The Forward on the exceptional status of c-sections in Judaism:

Jewish law is straightforward about cesarean births: permissible to save the lives of mother and child. And yet, the product of that birth is somehow perceived as less natural. A bris of a cesarean-born boy, for example, does not supersede the Sabbath, unlike that of his vaginally born brother. A Pidyon HaBen, which is the firstborn son’s “redemption,” does not take place for cesarean-born boys, because the child, in effect, is not the firstborn of his mother’s womb. Rabbis seem to have taken a “Macbeth”-like approach: In Shakespeare, a C-section makes a child “not of woman born.” This was not the way we were meant to birth. The Mishnaic term for C-section was “yotzei dofen,” meaning “out of the wall [of the abdomen].” It’s a phrase that modern Hebrew linguists use as synonymous with “unusual” or “exceptional.”

As the mother of a daughter born by C-Section, I'd like to note that in modern Hebrew it can mean 'exceptional' in an entirely positive sense as well....