Cal's parents want a second opinion on her genitals, so they take her to the doctor who screwed things up in the first place: Dr. Philbosian.
He refers the Stephanides family to a doctor who refers them to another doctor in New York, so off they go to the big apple.
It turns out that Dr. Luce is the head of the Sexual Disorders and Gender Identity Clinic at New York Hospital.
His waiting room looks like an erotic museum exhibit. Even the paperweight is a penis.
Cal tells us that "Peter Luce was considered the world's leading authority on human hermaphrodism" (4.1.69) and the rest of the chapter is a combination of hermaphroditic history and Calliope's psychological evaluation.
All you need to know about Calliope's psych eval can be summed up like this: She lies a lot to make herself seem normal… whatever normal is. Oh, and she and Dr. Luce watch porn together. You know, like you do with your doctor.
Back in the hotel room, Calliope has a crisis of faith when Milton says she can come home "Soon as [she's] better" (4.1.195). She wonders what he means by better.