My users love my boobs^W^Wme.

In all seriousness though, being a female in support role like this has advantages. The whole mothering/compassion instinct tends to take over quite frequently. "My network is my baby and I must protect it!" is the attitude I tend to take at the office, even if it means threatening to lay the smack down on my users. :) (In jest, of course.)

(I wonder what the female equivalent of BOFH would be...)

I tend to agree with you that there isn't (and shouldn't be) much difference in ability, but it may just be the nature of the work. Now that I have a think about it, it could largely be because IT people have positions of power. Most power figures in history have been men, which I think ties more into the hardwiring of male/female brains and the whole notions of alpha males and whatnot. Men like power, men like to control. But, thankfully, it doesn't always work out that way (see my example below), and I think the amount of women both in power and wanting power is increasing. I just think it's yet to hit the IT sector as much as it has in, say, politics.

Funny example: When I started my job, I was a junior admin working under this coarse, domineering man who refused to do his job and refused to be contactable when he was out. He always had this "I am holier than thou" attitude and generally Long story short, I have both his job and his BlackBerry now. And our systems are far more stable, too. :)