There are studies showing a drop off in interest in math and science among girls as they go into high school. The common explanation is puberty- and no, not because hormones mess with girls' brains, but because of the impact of the desire to be desirable. Girls who are interested in math and science tend to be labeled "smart", which in high school tends to mean "not dateable". And even for a "smart" girl, being considered dateable matters a lot in high school.
Of course, high school guys want dates, too. But some of the "smart" boys in my high school classes (eons ago now) got dates. None of us "smart" girls did. And before you trolls jump on that, it wasn't because we were all ugly- we're all happily married now. And I used to get hit on by guys who didn't know me and so didn't know I had that "smart girl" label.
I doubt high school has changed that much since my day. Actually, I suspect it has only gotten worse, given the female "role models" I see in pop culture these days.
I am very grateful for the very geeky college I went to, which changed me into a science major. I still didn't get that many dates, though- I found that telling a guy my major was a great way to get him to leave me alone. But I got enough to not start lying about my major.
This entire thread is half sad/half funny, because the same old canards about why women don't go into X field are being trotted out. Yes men and women are different, but as one of the previous posters mentioned, not as different as you think. I don't have the time or interest to go through and counter all of these silly arguments. But I did want to say something, in case there are some young geeky women reading this thread and getting more discouraged.
I ended up with a PhD in science and a serious interest in the application of computers in my field. I am now the head of the IT/informatics department at my company. My husband (a programmer) works on a team with several women, one of whom is his boss. He speaks highly of the technical skills of his female colleagues, and he is not an easy programmer to impress.
I know quite a few women working in computer related fields, as programmers, database designers, and managers. None of us got an undergraduate degree in computer science. So really guys, I don't think you can argue that women aren't interested in computers. We are. For whatever reason, we just don't end up in the computer science departments. Look at the departments to figure out what is wrong- don't look at the women. We're just fine the way we are, thank you.
Oh, and I played with BOTH dolls and legos as a kid. So does my 19 month old daughter.