Outside of the fact that there have been studies that show having more women on a team increases productivity and communication, I don't think just knowing a change needs to happen is enough for a lot of people. A few men I've worked with have been completely oblivious to women's issues and wouldn't otherwise make an effort to do anything about that. Just having a woman on the team can adjust perceptions about capability as well as make some of the issues we deal with more "real".