The Casual Vacancy is really, really for grown-ups. The novel says that the cleavage of one character "radiated little cracks that no longer vanished when decompressed," and tells us about a young boy who has "an ache in his heart and in his balls." A woman visiting a housing project sees "a used condom glistening in the grass beside her feet, like the gossamer cocoon of some huge grub." There is a "miraculously unguarded vagina," which I can only assume has already inspired at least a dozen works of fan fiction about Harry Potter and the Miraculously Unguarded Vagina.
Rowling explains that these sorts of subjects are one of the benefits of leaving fantasy behind. A crucial difference between fantasy and realism, she says, is that you can’t make fantasy too raunchy. "You don’t have sex near unicorns," she says, "It’s tacky."