Hmm. Perhaps I didn't make it clear in my original post that this consideration applies mostly in school (I was told once in school that I shouldn't take a class because I might be the only boy in the class!), and in University. Basically, any educational institution that involves computers and young males.
I wasn't saying that women conciously make the decision to join some exclusive club. But I saw what happened to women that dared venture into the computer rooms in school and university. Basically all the women were hit on, especially if they showed any talent. In uni it wasn't so bad, the geeks were more subtle by then with their urges. But if you knew any body language you'd spot them doing it a mile off.