i don´t think Du can get a perfect answer...i mean, i got most otaku Friends that are girls..but again..you would have to take the biggest otaku test ever to find out^ ^(sorry about my bad english!)
I'd say that there are Mehr male Otaku, but then again i've only ever known one female Otaku and she was my cousin (and the sole reason of how i got into this)
Wowee.. I don't know... Even if I generalise it to one series, like Naruto.. I kind of know the same no. of fans.. Maybe Mehr girls, because I'm a girl and I meet Mehr girls than boys in general..
... Du could plan out a world wide Otaku meet up which could be compulsory to attend..Maybe then you'd have a correct answer....
