Question to Christians about God, if your uncertain about which Gender God is, why call it a He?

I mean, supposing if he does exist, how do you know he is a Male, maybe he's a Female, maybe he's both, maybe he's Aual, maybe he's another Gender that is beyond human comprehension, or maybe there are more than 2 genders out there in the universe and he is his own unique... so why do you call it a He, She, or even a It? It could be something even more complex.