I don't think I'm an accurate guesser, especially when it comes to sensitive or "feminine" guys and androgynous or cold/dry girls. The signals I pick up for male/female are easily mistaken, especially when people are less gender stereotyped, which I think is a good thing. I don't believe in a gender dichotomy.
I've observed some particular patterns in the way men tend to talk about their ideas compared to women, but nothing definite, and it's hard to describe particular examples. Something about the amount of pronouns, sentence flow, specificity....
I'd guess, from my short time here, that you're male. That's my first impression, but I wouldn't be at all surprised to be wrong. I'm glad that gender =/= personality or behaviour.