Zak S asks why none of the guest stars on I Hit It With My Axe could get any boys to let them play when they were teenagers. (NSFW)
If I had to hazard a guess, I'd say the answer's in the gap between:
"When I was a teenager, I knew guys who were playing and I always wanted to try it, but they wouldn't let me play."
"Heh, that never happened with us. Sure, we were nerds but we weren't stupid...and we had hormones just like anyone else. If a young woman would have asked to play D&D or whatever we were playing we would have each been falling over one another to day "yes". We were not at all shy, and every one knew that we played...but no girls asked." (Mr. R, from the comments on that post)
One of my major social functions is to make it okay for the women around me I hang out with to be geeky, because there's always at least decent odds I'm the geekiest one in the room, male or female. Comic books, video games, and, yes, D&D, are all often seen as "boys stuff." Women are often interested, but aren't sure how to directly ask. And male nerds tend to be even more clueless than guys in general.