Jammer, when you say "establishing a set of ethics," I'm not sure what you mean by that -- can you say more about that, and maybe give some examples of the sort of thing you have in mind?
As to the different needs of women, Kathy's mentioned a few, such as the ways women differ physically from men, and how that affects things like what are comfortable ways for them to carry; the difference in men's and women's initial mindsets, such that men are likely to need to learn to be less aggressive, while women may need to be taught to be more so. (IMO, the latter, by itself, is a reason for offering classes just for women.)
The fact that many men do posture (and sometimes behave inappropriately in other ways) has also been mentioned as something that keeps women from wanting to join coed classes. It's annoying, it's a huge distraction, and it's not our job to educate them, or put up with them. When we're paying good money to learn skills that may be needed for our survival, we have a right to be able to focus all our attention on what's being taught.
And here's another thing that hasn't really been touched on: the threats women face are, statistically, very different from what's likely to happen to men. Specifically, women are
much more likely to be victimized by men they know: current or former intimate partners, or men they've met socially (think "date rape" here). At a certain point, ethical
self-defense training for women must address that.
If you haven't read the thread I referenced in first discussion,
Wo/Men, Handguns and Self-Defense, you might want to do that -- it brings up all sorts of ways that self-defense is a very different proposition for women.