AN: I've yet to write in this fandom, but I love the show. R/R if you please.
Guys his age were anything but subtle in their opinions of the school's female populace. Ichigo was one of the few exceptions. Perhaps it was because he was a bit more well mannered despite his badass rep or maybe it was because Ichigo respected woman in general. It still stood true that Ichigo was often accused of being gay because he didn't openly express appreciation for the female form like his lewd classmates often did.
It was there, but he didn't have it in the open. He didn't talk about how hot it was when girls wore miniskirts, nor did he thank the lord for his good fortune if Inoue's blouse had a gap between the buttons.
Maybe that just didn't need to be brought up. He hit anyone that questioned his masculinity, but he knew that his interest was there. It just wasn't in the open.
It was in the subtle swing of shiny black hair, it was in tiny feet and delicate wrists. All men, openly sexual or not, have preference. What business of his classmates is it if he thinks small breasts more attractive, and short and petite more becoming than voluptuous? He rests assured, because he bets that he's not the only one who likes something specific.
Ichigo didn't read Playboy, or stare at girls bottoms for the heck of it, but he was not gay. He appreciates that smug smirk, the curved calves and the like that make up his preferred object of attention.
Sometimes he notes that his favorite things in a girl are all strangely specific. A bit too specific to not consider the implications.
Rukia and Orihime were two different kinds of pretty. If the former was just more so in his minds eye than so be it. It didn't make him weird.
So when Keigo or his dad question his masculinity, his lack of a girl friend, he doesn't really care enough to be truly offended.
The only way to convince them is to allow them to read his thoughts while Rukia is fighting a particularly stubborn hollow, and her eyes are hard and sweat makes the hair at her neck damp. They would have to be in his head when she gushed cutely at a rabbit or when she pouted after not getting something she wanted. That's how he would prove that he's straight.
If they only knew that there is a reason he tolerates her painful high kicks. She is far too pissed to consider the view she is permitting him.
So Ichigo doesn't stare down girl's shirts. That doesn't mean that he's batting for the other team. Keigo and his dad may accuse him otherwise, but he knows that it would be different if they read his mind. Not that they can or want to. Maybe that's for the best.