Perceptive?  Ryouga?  This guy falls for it every time Ranma changes
clothes and announces she's his long lost relative, and he saw through
Ukyou's disguise?  

This would, incidentally, have been when Ukyou and Ranma were 13, (1st
year of junior high).  The odds are pretty good that Ranma's voice
was pretty high pitched as well, or just starting to break.  

Isn't this a repost?