Mary,
I'm afraid that a lot of it has to do with the move to bigger, more powerful boats. Body size is a genuine limiting factor. For the last few years, the ONLY boats with boards and big classes have been in the 19-20 ft range. As a 140lb guy, I have a great deal of sympathy for these women. The sheet loads are immense, and the "average" female crew/skipper combo on I20's, P19's, N6.0's, and Tigers would carry 30-60 lbs of correctors AND be unable to right the boat.
We have one of those rare commodities (female owner/skipper) in our Taipan fleet, and I think more will join. It's simple: you need a boat with light sheet loads, a small spinaker (if any), and one that is light enough to move around/right. I believe that the Stealth was also designed with this in mind.
If you think there aren't women interested in the sport, you need only to look at college racing - TONS of women compared to cats. You just need boats that are technical, or strategic, rather than being about pure muscle.
Just my opinion
Michael Coffman
T4.9#32