<p>Like Greybeard said: in countries where gender roles are less stereotypically defined (for example, Sweden), women tend to do better at everything that’s not considered particularly feminine, not just math tests; they have a higher percentage of women in politics, etc., than most other countries. Correlation does not always imply causation, but in this case, it makes sense. </p>
<p>@LogicWarrior: The valedictorian argument hardly holds up. Being a valedictorian means by its very definition that you’re one of the top, top students. Being a boy or girl does not, and I can’t see how it would affect that at all (unless, of course, you’re told such things as “boys/girls are less clever/less good at reading/less good at math than girls/boys,” - delete as appropriate)</p>