Hidden beliefs in science stereotypes predict size of gender gap across 34 countries

Please go read Ed's excellent piece on how biases and the gender gap in the sciences feed off each other.
Among the findings:

So the more a nation believes in the stereotype of the scientific male (even unconsciously), the greater the gap in performance between boys and girls in both science and maths. In fact, these hidden biases were a better predictor of the gender divide than what people actually said about science stereotypes. These explicit opinions accounted for about 2% of the international variation in the science sex gap, while implicit associations accounted for a much larger 19%.