Stephen King has forgotten where he got the idea for his first novel, Carrie, he told interviewer Charles L. Grant. At the time, about 1970, he was writing short stories for a men's magazine called Cavalier.
“Then, as I started to publish more, some woman said, 'You write all those macho things, but you can't write about women. You're scared of women.' I said, 'I'm not scared of women. I could write about them if I wanted to.'
“So I got an idea for a short story about this incident in a girls' shower room, and the girl would be telekinetic. The other girls would pelt her with sanitary napkins when she got her period. The period would release the right hormones, and she would rain down destruction on them. (I have to admit, though, that this hormone thing wasn't very clear in my mind.) Anyway, I did the shower scene, but I hated it and threw it away. My wife fished it out of the wastebasket and read it. She said, 'I think this is pretty good. Would you go on with it?' So I did. And I really got sadistic about it. I said, 'I can't have her rain destruction on them yet; they've got to do more to her.' So they did more, and they did more—and finally it wasn't a short story, it was a novel. But I can't remember the real kernel, where the idea came from.”