Haha, there isn't really such a mystery with most authors most of the time, though, right? I don't know if there's any sensible basis to doubt that Ritz is a woman. Kuroda bb, as well, is clearly male if that was who was being referred to. Namori...I don't really know what is going on with him/her that is causing rumours, but from his/her work I always got the sense that Namori was definitely male.
In general, I always feel that you can sense a clear distance from reality in male yuri mangaka's works. It's not necessarily a bad thing, as there are genres where that's simply not altogether important (comedy, porn, school life, etc.) so there's certainly enough room for great works to be made and for them to survive in the ecosystem. On the other hand, I haven't found any work by a male yuri author which has struck me at all on a deeper level thus far. For any genre outside porn, my favourite yuri mangaka will tend to be always women by far.
It comes down to factors like lacking the straight-up life experience, and idealization being part of the original appeal for yuri in the first place. But I figure a lot of male yuri mangaka are simply not equipped or mentally comfortable enough to step into telling real, grounded stories. I mean, you've got things like the casual way Takemiya Jin threw in the fact that Kurosawa had a 'physical'/exploitative relationship with a guy in this story. To a woman, that sort of thing might simply be an ugly, grim, but ultimately plain fact of life. However, I can only imagine how awkward a male yuri mangaka might feel about introducing elements like that into their story. It's the presence of factors like these that frequently make it pretty easy for me to figure (I feel, at least) if a yuri author's a man or a woman.