"Here’s a really interesting experiment to try, if you have the opportunity. Visit an elementary school classroom. First, just watch the teacher interact with the students while they’re teaching. Don’t try to count interactions. Just watch. See if you think that any group of kids is getting more attention than any other. Most of the time, you probably will get a feeling that they’re paying roughly equal attention to the boys and the girls, or to the white students and the black students. Then, come back on a different day, and count the number of times that they call on boys versus calling on girls. I’ve done this, after having the idea suggested by a friend. The result was amazing. I really, honestly believed that the teacher was treating her students (the teacher I did this with was a woman) equally. But when I counted?She was calling on boys twice as often as girls."
I’d love to try this experiment out at my school, but I suspect I will not, and will instead ask my colleagues to try it out on themselves. Like Mark writes, this does not happen because the teachers are sexist, I’m sure they do not feel that they are at all sexist. These problems are systemic in our society, and you need someone on the outside looking in to have a chance at noticing them.