I'd like to say that while there is no direct evidence in the manga to
support the claim that Ukyo is legally a guy.  There is circumstantial
evidence that points to her being legally a man.
1.  When she is first introduced at school, it is as a guy by the
teacher.  In American schools, at least, you have to provide a birth
certificate to the school when initially enrolling your child.  I'm
sure Japan is similar.
2.  She went to an all-boys school at some point in her career.  I
don't hink that they would let a girl in if her parents said something
along the lines of , "Well, we're raising her to be a man."

In conclusion, I must state that there had to be something that
legally stated that Ukyo Kuonji is male.  Therefore, if it is a fanfic
convention that she is legally male, it is one based on both the manga
and anime.

	I believe that the often reached conclusion of this debate, 
along with the "Ukyou is Ranma's Best Friend" debate, is that there
is NO REAL evidence pointing in either direction.  There is a bunch
of circumstantial evidence that can be interpreted in many ways, but
as I'm sure we all know, circumstantial evidence is just that, 
circumstantial.
	Basically, if its convenient for your plot, use it.  If you
disagree with it, don't.  I think that about outlines it, ne?  
	I need to go back and write instead of reading my mail...

-skeezy5