I attended a developer event on Tuesday. I wasn't planning to go there - I am fairly new to iOS and didn't expect to understand much of the presentations - but went on impulse and understood enough to make it worthwhile.
Before the event I read their Twitter feed, and noticed a journalist asking how many female developers are attending the event. My first thought was "oh no, poor organizers, now they will feel the need to apologize". And sure enough, afterwards I told the journalist that I was the only woman there (out of about 30 people), and the organizers felt the need to inform us that they'd love to have more women and don't want to be a male-only club.
(For a second there I considered lying and telling the journalist that 25 out of 30 attendees were women to see how she'd react, but it's not really all that funny if you don't get to do that in person.)
This is by no means criticism of the organizers. They just said what was expected of them. More to the point, I knew that they would say it at some point as soon as I saw the original question. And that, people, is really something. I am not the kind of person who easily notices such generalized social pressure; usually subtle social clues have to be beaten into my head with a two-by-four at a considerable personal risk to the beater. If even I notice things like that, the pressure on everyone to explain why they don't have more women must be enormous.
But seriously, why? It makes sense to discuss why there are fewer women in the CS/IT field than could be, what can be done to attract them, should anything be done, and how, but what can realistically be expected from the organizers of any specific professional event? They announce the event, they choose the speakers, they invite people to come, and some of these people might or might not be women. It should go without saying that women are welcome there, but it obviously does not in fact go without saying. Makes me wonder who needs it to be said explicitly, and why.