He Said, She Said

While our class was editing various papers of anonymous classmates today, my notes weren't on how to revise my own paper. Rather, I was tracking and tallying how my classmates referred to the writer of the paper. The results were shocking. The females didn't mention gender in their references to the author, while the males generally assumed the author was a male.

So does this mean all the males in my class are sexist? I don't think so. But what does this mean?
This theme can be seen throughout pop culture. Why is g-d always referred to as a he? Why is mother nature a she? Is does seem slightly racist that the dominant, all powerful force is a male while the caring, motherly force is female. And, I do believe ,these are sexist assumptions. But I still refuse to believe my male classmates are sexist.

I'm stuck. It would be one thing if both males and females referred to the author in the same manner, but they don't. So, do males assume an anonymous is a male because their sexist, egotistical, dominant, or just from basic instinct? And why is it that females make more asexual assumptions?