It's not in Cambridge, but the best answer here is Fenway health. It's worth the trip into town, and while it can be difficult to get an appointment with your PCP, you can usually just make an appointment with any provider in the building and they will be covered by your HMO as if you are seeing your PCP.

They're very sensitive and knowledgable on these matters.

Honestly, it's purely business. Lesbian bars don't bring in money, gay bars do. I lived in SF and frequented the Lexington quite often with my lesbian friends. That place was DEAD, ALWAYS. It's not a surprise that these places don't stay open when the nearby gay bars are always packed.