Equal pay still is the #1 issue, in my opinion.
I also think a growing issue is child-friendly workplaces. I often speak to or read of women who are afraid even to mention they have children! That's a frightening situation to me, but I know that prior to kids, I really didn't think about how having them would impact my career choices.
Another "mama" issue is being given adequate time/space to pump while nursing. Legally employers are required to provide this time, but the guidelines are iffy and not always followed.