I would hesitate to say that's a reason for gender specific classes.
Yes, behavior changes according to the gender dynamic of the group, but those changes don't inherently make one better then the other for teaching shooting.
Example: As a kid I played soccer. I played one season on a girls only team. The one and only time I ever played on an all girls team it was a revelation.
I hated it. I loathed the constent and overwelming female interaction. I spent the rest of my teenage years playing on coed rec teams. The behavioral gender diffrences evened out and allowed for a more pleasent experiance.
Some people relate better in single gender envirnments, some people relate better in coed environments. The oppertunity for the induvidial to choose which environment meets their needs best would probably be the optimal goal.
Specifically, for shooting, I think woman are more likely to be more comfortable in female only classes for multiple reasons and I don't see why that should change the end results in terms of how well they learn the material nessesary.
Secondly, there are things that are gender specific in self defence training that do need to be covered for that gender, that may or may not be relevent in a basic shooting class.