Ok, I implemented something by hand which does MOST of what I need.
1. Most of this mod is the "manage boards" code, changes to profile, etc. and basically housekeeping for the new fields. I don't need this.
2. A bunch more of the code has to do with age and age ranges -- again, I don't need this.
I got it working so women see all boards (plus women's only) and men see all boards (plus men's only)
However, if I bookmark the men/women forum, and try to access it from the other gender, it is allowed.
I need to add this restriction, and then I should be good.