There is a fantastic article at grapplearts.com about attracting women to and keeping them going in BJJ.
I personally really don't care whether I wrestle guys or girls. Right from the beginning, I had no issue about being the only woman in class most days. But it's sad that there aren't a whole lot more women involved in BJJ. There are just so many good things things that come from training, and there are so many women who would benefit tremendously.
The article addresses a lot of the issues and makes excellent practical suggestions. Hopefully, if more schools put some of those recommendations into practice, there will be an increase in the number of women joining and staying.
Our school is only small, and women's only classes would be hard to justify. Aside from myself, there are only very sporadic showings of females. I guess if I could see that there are some interested ladies, I would happily volunteer to be assistant instructor, to help get some newbies through the first few tough months.