I can’t remember if it is in the short-story or the book, but there is a scene where Ender has to talk to another cadet—a female—and she is naked. His response is sort of a numb, so-what? The idea that they might have some type of relationship doesn’t seem to be a possibility in his mind.
He was like 8, she wasn’t much older. Not exactly a lot of hormones or development there.
That was Petra Arkanian, when he was promoted to Salamander Army.