Some callers (Mary Panton springs to mind especially) have made a speciality of completely genderless calling.

One of our regulars starts off with something like "Purely for reference purposes, I'm going to call the people on that side of the set [points] with their backs to the window 'men' and the ones facing them 'women'" or similar.
This has the dual advantage of
(a) making it clear enough that you don't literally have to be the specified gender
(b) dropping a gentle hint to any M-F couples that are the wrong way round.