From my understand of reading that book;

1. Core-self is gender neutral (below Brahman effulgence levels)
2. But core-self has a gender when it transcends to Celestial worlds like shivaloka, Vishnu Loka. (That's what the book talks about)
3. Subtle body will have inclinations or interests towards one particular gender or multiple. That's where one has to track down, why and how it came. 
4. Geographically, track where the gender interests in subtle body is stored and operated and see if you can remove it or control it.