Jon smiled and started to go to class, knowing that because no one heard his wish, he got away with it and Sarah McMillan no longer existed. But, of course, since he was also no longer really himself, Jon Gibson no longer existed either. He was a brand new person. Half Jon, half Sarah. And since Jon and Sarah were two different genders, this new person was a completely new third gender.
He ran into the school and into the nearest restroom. He wanted to check out exactly what his new body looked like. Yes, he had Sarah's breasts and long blond hair, but what other changes were there? And what didn't change?