Character Analysis
Petra probably has the coolest back-story of all the girls: she's a former boy band member. She's biologically male, and entered the pageant to change viewers' ideas about gender and to make enough money for sex reassignment surgery.
In the (Island) Closet
We don't learn that Petra is transgender until almost a third of the way through the book. Because of this, readers (like the other beauty pageant characters) get to know her as a person before being able to judge her based on stereotypes.
While we're getting to know her, Petra just seems like a girl who loves fashion, is generally helpful and encouraging to the other girls, and desperately needs the medicine that's lost somewhere on the island. As far as being transgender goes, her hallucination story about a toad that knows that it's a princess on the inside may give a pretty decent clue, but it takes Tiara seeing Petra peeing for the secret to get out and be discussed aloud. Even when confronted by the whole group of Teen Dreams, Petra opts to come out to the group rather than force Tiara to keep a secret she finds uncomfortable.
She's also thoughtful, picking up on the needs of others even when they're not talking to her directly. When Mary Lou loses her purity ring and Adina makes a crack about the ring, Petra tells her, "Just because you're funny doesn't mean you get to be cruel." (13.215) She knows the ring is important to Mary Lou, and even though the beliefs behind it aren't her own, she puts Mary Lou's feelings first.
Petra and her Pirate
Coming out to the group was hard, but Petra did it bravely. For her, coming out to the hot pirate Captain Sinjin is scarier. "She wondered what would happen when he knew the truth. Would he be able to see past what was and see what could be?" (21.212) Petra can't imagine a boy falling for her, knowing that she is transgender.
The way she spills the beans is out of necessity, rather than by choice: she pees on another pirate who gets a jellyfish sting to neutralize it, in front of everyone. Who knew peeing could be the key to people finding out your secrets, but also saving lives?
Sinjin isn't scared off, though. Petra makes sure he's in it for the right reasons. "You know who and what I am. So if this is just the old curiosity shop, you can stop right now." (22.64) When he responds by kissing her, she finally allows herself to fall for him. Hard.
Even though Petra had to hide her biological sex to compete in the pageant, once everyone gets to know her for who she is, they're totally accepting. And that's a pretty big political statement. Right, Ms. Author?