My guess is also female, but it is just a guess. From the picture, it has the larger lower body that females tend to have, but it could be the angle. The neck also looks reasonably chunky behind the head, another female trait I think.
We have a skink that we now think is male (originally believed to be female, as it was housed with another quite "male" male), based on several observations, but one was the way it reacted to another verified male; they were allowed minimal interaction through mesh, and the result was plenty of aggression. Although males and females can all fight each other with relative lack of abandon it seems, this was the final thing that convinced us that what we had was *probably* another male.
Actually, I may post a pic of him to see what everyone else thinks
PS its a really pretty skink!