I'd agree with Jessi that there is still a sort of differentiation between what is expected from writers based on gender. I think that mindset had a lot to do with the hype around 50 Shades of Grey. People were amazed that a woman could know about BDSM and actually write about it.
This title goes back a bit but The Story of O was definitely hot and kinky and was written by a woman, Pauline Reage. This French novel dealt with S & M and B & D. It was also made into a film.
As well, Anne Rice wrote a series of books which were erotica, and I think were also S & M. I think they were titled the Beauty trilogy after the fairy tale. Really. So the critics who were so surprised that 50 Shades was penned by a woman obviously need to brush up on their history of erotic literature, because these were pretty big titles. I am sure there are more but these are certainly not obscure.
Ryder13