Ace Sanchez wrote:

Some time after I found out about Ran-chan's curse, Tsubasa found me. I

had

given him a picture of Ranma to prove that I really had a fiance. It was a
picture of Ranma's girl side, of course. I had been pretending to be a

boy..I

didn't want anyone thinking I was a pervert or anything!
Tsubasa showed up to try to get rid of Ranma. Somehow he wound up falling

in

love with his girl side. And then falling in love with Akane. There was no
hope for that kid. Any non-boy that was nice to him would do. However, it
seems that Tsubasa knew I was a girl, and had known all along. Akane was
right, he wasn't really a pervert..unless you count the crossdressing. But

who

am I to judge someone for crossdressing?

Didn't Ukyo know all along that Tsubasa was really a boy who cross-dressed?

That's correct.  The confusion arises in translation since it is almost 
impossible to talk about someone without revealing their true gender in
English, but the same is not true in Japanese.  This is part of the 
reason why gender confusion stories and subplots are so much more common 
in Japan than in English now that the days of boy actors playing female 
roles are past. 

However, Ukyo did think that Tsubasa was a homosexual boy and that this 
was the reason why Tsu-chan was interested in her.  Doubtless she hoped 
that by affirming her "heterosexuality" with Ranma-chan's picture, she'd 
have a better chance of discouraging the little limpet.  In the story, 
it would only take a slight adjustment to take this into account.