<p>Other than some people being initially surprised to find out my major (or to see a girl in their CS class), I generally haven’t been treated any differently than other CS majors are treated.</p>
<p>As for why there aren’t many women in CS, I think a lot of it comes from some kind of stigma that it’s only for guys. I know there have been quite a few people (mostly other women, to my surprise) who are shocked that I’d go for a “man’s major”. In that sense, it may be a kind of self-fulfilling prophecy: Women think that they shouldn’t major in CS because of the amount of men that major in it, leading to fewer women majoring in CS and maintaining the high male:female ratio.</p>
<p>As Reactor said, other than stereotypes CS is a very gender-neutral field. I mostly get the kind of reactions mentioned above when talking to non-STEM majors.</p>