Differences between men and women have always been identified, whether through popular novels, such as Men are from Mars, Women are from Venus, or through gender specific media. The differences cannot be ignored.
However, when you want to reach lesbians, is targeting the entire gay population enough? The answer, as I am 
hoping you already knew, is no. Where reaching gay males could be the equivalent to the “mainstream” population in the straight world, in the gay world, I think the majority lesbians step down from “mainstream” status.
Reaching lesbian audiences is even harder than reaching Hispanic audiences. Whereas Hispanics have strong national organizations such as League of United Latin American Citizens and the National Council of La Raza, few lesbian national organizations are household names in many lesbian homes. There are few print outlets and not much TV programming for lesbians, especially in non-cable broadcast networks. Logo is only available to digital cable subscribers and Showtime’s L Word is not available in the standard cable package.
I think one of the best ways to find a targeted minority audience such as a specific lesbian group is through grassroots marketing with the majority of the work done by word of mouth testimonies. Several events do a decent job at gathering large numbers of lesbians such as Dinah Shore week, Pride month celebrations in Provincetown, the Michigan Womyn’s Music Festival, the National Center for Lesbian Rights National Dinner in San Francisco and the Mautner Project Dinner in D.C.
Participation in these events will let you in to certain types of lesbians, but not all. You will reach the free spirit lesbian, a slightly older group of women who can afford trips (and time off) to Dinah Shore week and Olivia cruises, health advocates and the politically conscious. The lesbian community is very spread out and each group is very different from the next. Reaching us all takes a very targeted approach, which has yet to be mastered.
Please feel free to comment on this post. What has worked for you? How would you approach this situation?