One Door Closes, Another Opens
At the end of the novel, Cal has returned from being a performer in a sex show in San Francisco, his father has died after being blackmailed by his brother-in-law, Cal has realized that religion is a crock, and Desdemona has finally confessed that she and Lefty were brother and sister.
That ending makes Titanic look uplifting. Strangely, though, Cal remains optimistic. "I stood in the door for an hour, maybe two. I lost track for a while, happy to be home, weeping for my father, and thinking about what was next" (4.7.198).
What we've read has basically been one giant epic coming of age story, and Cal has finally arrived. He's happy to be who he is, telling Desdemona, "I like my life" (4.7.187). And now that his life is basically in order, Cal has accepted the fact that fate and free will have combined to make him, and he's kind of excited to go along for the ride.
Due to the structure of the novel, we know that Cal's journey as an intersex man is never going to be easy, but we also get a glimpse at the beginning of the last chapter into his burgeoning relationship with Julie Kikuchi. This could be the beginning of a beautiful relationship.