The real question is why he made Aliss a male in the first place.
To make it a little different? To introduce a race where tits doesn't immediately equate as female? Lots of possible reasons really.
So, I don't know whether the author wrote the codex entry on Ovir and he simply wanted to make a race that's a little different, or he drew from what was already there, but the Appearance section says the following (paraphrasing):
Children look identical and can only be differentiated by medical sexing, till they reach adulthood. Many communities who frown on that procedure therefore treat all children the same, and let them choose their gender roles on their own once they reach adulthood.
From this we can assume that gender might simply not be a big thing to Aliss, and a large section of Ovir, at all (as I said before, its just a technicality). The author states Aliss' gender to introduce the race and make you aware of this difference, then continues to treat her like a female because that's a resonable assumption of her gender from a human (or any of the avaliable starting races) standpoint, and leaves it at that not makind a big deal of it.