Women in Male-Dominated Professions?

I'm not sure if this is something all women do, or if I just have a lack of confidence in my own abilities--or if this is something that I'll slowly grow out of. (This isn't to say I'm a spring chicken; rather, I'm saying that I'm not as young as I used to be nor as old as I hope to one day achieve.)

But I have a constant lack of confidence in my abilities. I don't think that what I'm doing is "good enough"; instead I think what I'm doing is, in fact, barely enough. I've had friends point this out to me. I recently asked a friend about a professor whose course I will be taking over the summer, saying to him that I'm terrified of screwing it up, that I'm really afraid I won't be good enough to do well in the course.

He replied to me, "Whatever academic failings you seem to think you have, you don't. You'll do just fine." Which was a very nice way of him to point out my tremendous lack of confidence.

And then, recently, I was given tremendous compliments by two different people, neither of whom knows the other, but both of whom seem to think well of me. They both admire what I do, and the compliments are those that I can't just shake off as meaningless. I have a lot, a ton of respect for these two people, and all I can do when they express their compliments is panic, worried that I'll disappoint them.

Is this all women? I was recently speaking to Carol, of CarolsLib fame, with whom I'd also had the humor discussion. She said that she always focuses on the negative in her workshop evaluations, that if there is one thing that is negative, she wonders what the problem was. Do men do this? I've got a lot of male friends, and although they have their confidence shaken on a regular basis, it seems as if they started from a high point of confidence, and if it has been shaken, it drops. It seems like women, or at least I, build confidence from the ground up; I sort of feel like I'm working from the base of nothing, and I have to make something out of nothing. (Which sounds negative, I know, but it really does produce good professional results.)

Is this all women who work in male-dominated professions? I'm not sure. It actually may be. Is there an endemic sense in women who work in these professions that screams at them, "I don't belong here." I know that there have been times when I've discussed complex technological issues (often BSD or Linux-related) with people, and it's taken them a few minutes to realize that I really do know what I'm talking about. It's not only men who commit this error, and maybe it's because I use flowery, grammatically-correct language to discuss things, but I do know that there is doubt at first--usually easily dispelled.

And it could just be that, since I grew up in a family where, when I received a 98 on an essay, my mother would ask, "Why wasn't it 100%?" I'm just constantly in search of improvement, of perfection. While it's something that hurt my feelings at the time, I do believe that my mother really improved my job performance and the quality of what I put my mind to.