Being that this is a story that displays hermaphoditism through the eyes of a teenager, it's no surprise that a lot of the book is centered around the physical body. Most of the scenes with Dr. Luce really emphasized what had already been the present throughout most of the book about the importancy of physical attributes as well as physical attraction.
The scene where Luce shows porn to Callie to see what sex she was attracted to really bothered me. Being physically attracted to someone, to me, doesn't necessarily mean you're more male or more female (especially thinking about the controversy surrounding the idea that changing your gender is a way to escape homosexuality). Judging Callie's dominent gender based on sexual attraction wouldn't show the type of attraction that Callie has for the Object which to me is a better indicator of her gender than anything. Of course Luce wouldn't know Callie's feelings about the Object because Callie is hiding that from him, but I felt like a lot of his questions were only surface level questions since most of what he's basing his diagnostics off of is in fact gender sterreotypes.
It just makes me think about how sex can never determine your gender in the way that Callie's physical appearance (the way she carries herself, speaks, write, ects) can never determine which of her genders is more prominent. I've felt throughout this book that Callie's hermaphoditism doesn't affect her as much as it affects people around her (her parents, friends, etc) which makes me believe that it's not so important to her.