this site purports to guess your gender from text you post based on some kind of "Women are from possessive pronouns, men are from definite articles" kind of algorithm.
After feeding it 10 LJ posts, I was tied 5-5. Number 11 said I was a girl. This post says I am female.
LJ entries where I posted photos were more likely to read as "male".
My "hey everyone, I moved; here's my new address" email was also "male". My last post to the thrift list was female.
have fun, ladies.
EDIT: fed it 10 of Ivan's LJ posts. 2 male, 8 female. Heh- my man is way more girly than I am.