I was really into Linux a decade ago, so decided to study IT. In addition to the haughty looks I got from some guys (200 of them, 3 of us) most of those felt the need to test my knowledge daily. Worse thing, they seemed to have a hard time remembering they'd checked I was 'ok', and again I got asked more questions. My uni email got hacked a few times. I would have felt quite singled out if I had let it get to me. Thankfully, I just happened to dress like Lara Croft (she copied me, not the other way around! I'm that old) and I was happy to show off my knowledge (even if that's not me) - so eventually things settled down. BUT the sexism was still there in the fact that some guys just kept looking for anything 'stupid' i could do. It's tiring to be constantly ostracized, however much you like IT, and after a few years like that, I stopped caring, said I didn't know the answer when people tested me. I lost the respect but they left me alone, happy they were to say, 'I told you! Just a girl!'. I'm not sure this will stop in my lifetime, but one bad apple is usually enough to put a lot of girls off. Why bother when society want you to care about handbags? Having to fight everyday for respect/acceptance isn't fair and ends up being a conscious decision. Thankfully there are a lot of lovely guys in IT and they should actively look out for the bad apples, as they're only would-be alpha males who feel threatened.
I could go on forever but I've got some photography jobs to get to (oh yeah, I left IT).
Still, thanks very much guys for the support, most of you are awesome people, who sometimes haven't actually realised you are.