I did non-stop research for about half an hour already, and I did not find much meaningful information regarding the United States. I only found one article that focused on gender in American K-12 classrooms.
Here's a short summary of the article:
- There are fundamental differences between the learning capabilities of girls and boys. The reasons for these differences are unclear, although biology is one of the factors considered. Regardless of the possible causes of these differences, educators must focus on equity, not equality.
- Girls, on average, receive higher grades than boys throughout middle and secondary schools.
- Teachers tend to give boys more attention since they are typically more aggressive and are more likely to have behavioral problems.
- Boys are more likely to be diagnosed with ADHD.
- Since girls get less attention, they get less positive or negative feedback from teachers.
- Stereotypes exist regarding what subjects are considered "girl" subjects and "boy" subjects.
- Despite the perceived stereotypes, gender gap in mathematics and science is closing (regarding enrollment and grades). It looks that this article was written a while ago, so I think the statistics are probably even more in favor of girls nowadays.
- Girls still lag behind boys however, when it comes to high stake standardized test scores.
- Females tend to do better in the humanities.
- Males tend to excel in technology related classes.