Beilock, who studies how anxieties and stress can affect people's performance, noted that other research has indicated that elementary education majors at the college level have the highest levels of math anxiety of any college major.
This in a larger article finding:
But by the end of the year, the more anxious teachers were about their own math skills, the more likely their female students — but not the boys — were to agree that "boys are good at math and girls are good at reading." In addition, the girls who answered that way scored lower on math tests than either the classes' boys or the girls who had not developed a belief in the stereotype, the researchers found.
Edit: The article linked above is gone from Yahoo News. But you can still see that via the Internet Archive's Wayback Machine. And here's a citation and link to the original academic article:
Beilock, Sian L., et al. "Female teachers’ math anxiety affects girls’ math achievement." Proceedings of the National Academy of Sciences 107.5 (2010): 1860-1863. (Link)