How do women's dress sizes work?

As a guy, I'm used to having things laid out on the line for me. If I want pants, I look for the ones that say 32-32, indicating 32 waist, 32 inseam. Your average woman, however, would go out to buy pants and look for a size 6. What's going on here?? Don't women need numbers too? There have got to be more measurements going on here, like for the hips, but they're ALL covered by one number?

This strikes me as insane. The one-number system would have to indicate that all women are proportioned the same way, which (correct me if I'm wrong here) is not the case. But the system must work, because I don't know of anybody trying to do anything about it.

So what is it? How has it come about? What do you women do when your size 6 doesn't fit right? Just throw your arms in the air and cry? Why do you put up with this crap?

Then there's the psychological factor...I don't figure that many women want to buy clothes by their measurements unless they fit the 36-24-36 mold. It's a lot more pleasant to buy a small number such as 6 or 8. This might be a silly reason for women's sizing, but a valid one.

Therefore the single size system, while it doesn't work perfectly for nearly anyone, is probably a necessary evil. The only ways around it are to have your clothes tailored for you, or of course, to make your own clothing.