The burning question here is, Are we talking about the Klingon side or Fed side?
On the Fed side, I do have a Female Klingon Tactical BO sitting in my assignments list.
On the Klingon side, I definately have one or two Female Klingon Tactical officers in my crew, but I had to buy them from the BO merchant. On the Klingon side, the "bridge officer commission" missions seem broken. In all my 45 levels, I only got a single female officer from there, and she was an orion. Even all of the Alien officers have been male.
On my 3 fed toons:
I've never gotten a uncommon or rare male klingon or any vulcans or either sex,
Gotten tons of rare saurians, and bajorans, bolians, andorians, trill, betaz's...and a couple fem klingon engineers.
Come to think of it - never got any humans either.
I figure its somewhat random... but I do want a vulcan or two for specific crew look reasons
I wish sometimes the reward would give you a choice between 2 officers because for some reason about 70% of the rare officers I;ve gotten have been tacticals.
I like how the first couple times (early on in the game) when you get an officer reward you can select from 3 or 2 options. Since then there is never a choice.