I think I read this story on BC rather than FM or somewhere, but I'm not sure.

A person had a sudden gap in memory; on day they're living as a man, and a moment later, months or years have passed and they're a woman. They panic, and after talking to people around them, they find out that they've got amnesia for the period when they decided they were transsexual and went through transition. Later, they find out that someone manipulated them into it, but I don't remember if it was by hypnosis or some high-tech or magical method of mind control.