You raise some really profound issues in your comment (a.ka. "rant" . Mainly, the question of exclusivity when an organization groups together based on specific simliarities, in this case gender. I'd like to respond to your post in first an anedoctal way, and then in a very actionable way (I hope).
First, I want to reiterate that the Girl Geek Dinners (GGD) and the other WiT organizations that I mentioned are not exclusive to men. If you care about the cause, you are welcome. The cause is addressing what we can do about the serious decline in female software technologists (Ref; NYTimes article: http://bit.ly/1ac11S) from 28% CS degrees in 2001 to 10% last year.
Now for two stories...
I attended a Women's Bond Club Diversity Round table at the New York Stock Exchange a few weeks ago. I will share more on the issues raised by the leaders of industry on my web site, but one quote really stood out. Lawrence Leibowitze, Group Executive VP & Head of US Markets of NYSE stated - (I roughly paraphrase ) "gender diversity isn't about a plot for a bunch of women to huddle to the side and discuss how they can take over power. This is about how we can get the cause gender diversity pulled into the center of core business. This is what we need to discuss. What we do here is relevant to society as a whole - driving awareness, as the workforce is only a microcosm of society. I am embarassed at how few men showed up today. Women should be required to bring a male executive with them". At this the entire room burst into applause.
Another story - curious about the emergence and growth of PHP as a development platform, I attended a PHP user group a few weeks ago. Now I am not a PHP coder, nor do I plan to be, nor do I feel like I could even play one on TV . However, when I attended the user group, I felt incredibly welcomed. I talked to various PHP coders and asked questions - on the object model, how it could relate to .NET, how we could interoperate with it, and I asked what could Microsoft better with PHP support on Windows. I learned that by participating in a community that I myself was not a member, that there was a natural sharing of ideas and integration around common cause - in this case, leveraging technology to do better things in the world. I found that some people didn't even know that PHP ran on Windows, and I myself learned more about the wealth of applications on PHP and think that perhaps we need to come up with ways we enrich our own Web App Gallery http://www.microsoft.com/web/gallery/
So I can think of 4 actionable things ( I hope that others to come up with other creative ideas!):
1. Women's organization need to really clearly indicate that all are welcome, should that be their model
2. Men should question, as you did, whether organizations like GGD are being exclusive.
3. Attend a community event even if you do not feel like a member
4. if you are a member of a community, (e.g. Women in Tech), bring someone who isn't, (e.g. a man)
I am so glad you raised this issue as oftentimes we shy away from topics that are sensitive. Hopefully by raising it, myself, you and others can demonstrate that diversity is a cause that brings us together, not sets us apart