Yes, it has always been an old boys club and that can be tough to break thru especially for women.  But, in the end one must do what one must do to get the job done.  I am sure LA and NY are tons worse.  SF is pretty laid back when you think about it.  When I first was looking for work out there a college advisor told me to get any job at a law firm I could get - any job, even if it ment clearing out the garbage.  Once in you have to find the right people to befriend in order to move  up and possibly reach my goals and he was going to help me with that but alas, I moved back to OHio.  I still keep his words close at heart tho - It isn't what you know but who you know that gets you ahead in this world.