This is a fantastic article on a topic I've been trying to get my head around for a while--the way great female fantasy and SF writers seem to fall off the cultural radar faster and more completely than male ones.
Most people remember Terry Brooks and other popular male writers from the 70s and 80s, but fewer people seem to remember writers like Katherine Kurtz, or even ones like CJ Cherryh and Mercedes Lackey, who are still writing today.
Rather than re-inventing the wheel, I'll post a link to the article here:
Fantasy, Female Writers, and the Politics of Influence by Tansy Rayner Roberts.
And as an interesting aside, did you know that Australia actually has more trade-published female writers of adult speculative fiction (and fantasy) than male?
Britain seems to have fewer, while the US is in between these two countries.
It's interesting how different English-speaking countries can be in this regard, but it does suggest that there's nothing innately different in the abilities of men and women as writers of speculative fiction.