In Flowers for Algernon by Daniel Keyes, the relationship between Miss Kinnian and Charlie begins to change. Miss Kinnian had been Charlie's teacher at a school for the mentally disabled, but as he becomes more and more intelligent, he begins to see her as a woman and a peer. He falls in love with her. Miss Kinnian, though, is concerned that he will soon leave her behind intellectually, and there is little hope for a long term commitment. She explains to Charlie the many levels of intelligence and how he is moving up those levels at such a fast pace, nobody will be able to keep up, including her. 

"'I can see only a little bit of that, Charlie, and I won't go much higher than I am now, but you'll keep climbing up and up, and see more and more, and each step will open new worlds that you never even knew existed.' She frowned. 'I hope. . . I just hope to God--'" (Keyes 22).

Miss Kinnian is also worried about the possibility that Charlie's intelligence will reverse itself, and of course, that is exactly what does happen. Charlie, at this point, does not see it coming because Algernon has not yet begun to regress. Miss Kinnian's fears, of course, are legitimate. It is very difficult to have a relationship with someone who functions at a much higher level than you. It is almost as if their roles are reversed. Miss Kinnian, in a way, becomes like the student that Charlie was in her classroom.