High SES schools:
These students are almost all headed for college. Socially, there is a lot of emphasis on social skills and appearance for girls. Girls are more likely to be encouraged to be a part of the group. Parents and some educators are more likely to question whether a daughter really has the ability, to take the most advanced math course they are recommended for. Even if they do, some believe it is better for a girl to be a part of the group and not stand out like that. Many families believe that girls are better at English and boys are better at math. High SES girls do very well in school, but are often discouraged from being in the most advanced math and lag their male counterparts who are rarely discouraged. Tellingly, the handful of girls in the top math class, often Multi-variable Calc., are often grouped near the top of the class and are likely to have an average score that his higher than the boys.
Low SES schools:
These schools have a very different dynamic. More girls are headed to college. More boys will join the military, learn a trade, or be incarcerated. The “don’t go to college” options are largely male-dominated paths (except for jobs like hair stylist). The imbalance in college plans leads to better balance in the top math classes. The top math class is also usually less advanced. It is more likely to be pre-calc or AP Calc AB. There are also many anti-college sentiment families in this group who believe the articles that say college is a waste of money. These are usually supported with anecdotes and ranges. The articles confirm what they want to hear.