i was reading through my friends' blog.... SHE took this test to find out what gender you have based on how a person writes, it turns out that she is a he. omg! i'm a man, that's how she titled her entry. so, i tried... paste a few entries from my blog and now im a guy.... siyyyyeettt!
here's a screencap [click for real size]:

see?!!? it even says, VERDICT: MALE. I don't know what's the difference of the genre: informal/formal. (who cares?!!) i nailed it both. i'm a male. (God!!!! ..............so, sorii). My friends' result was even better, she got a weak male verdict... and i'm more girl/girly than she could ever be... (and u just nid to trust me on this one) ....sorii nina! (we know why... berks.... right?!) so, why o why?!!? not that this is affecting me,its just that i could not believe it.....
just to remind you:
The system generates a simple estimate (profiling). While Gender Guesser may be 60% - 70% accurate, it is not 100% accurate. This is better than random guessing (50%), but should not be interpreted as "fact". In particular, men should not be offended if it says you write like a girl.
yah, make that Women, should not be offended if it says you are 66% and 80% male. the hell!!!!
anyway, you should try it: Gender Guesser