Differences in conformity: women may conform a bit more to widespread social views (at least, to views of "their social class") and/or compartimentalize more between what they learn about a specific topic and their general views. This would mean female scientists would be slightly less likely to be atheists in religious countries, female theology students would be slightly less likely to be fanatics in not-that-fanatical societies, etc.
We need to look at differences between men and women conditional on the fact that they've become economists, not just differences between men and women. Becoming a professional economist requires more nonconformity for a woman than for a man -- deciding to pursue a gender-atypical job, having peers and mentors that are mostly male, and delaying having children or putting a lot of time into family life until you're 30, at least.
Different subfields in economics: Maybe "economics" shouldn't be considered one big blob - there may be some subfields that have more in common with other social sciences (and thus have a more female student body, and a more "liberal" outlook), and some more in common with maths and business.
There are more women in fields you might expect to be more liberal, and fewer in fields like theory. http://www.cepr.org/meets/wkcn/3/3530/papers/Dolado.pdf Women seem to be more concentrated in public economics (taxes) and economic development. They are less concentrated in theory... and in the large field of "other". When you define the fields differently women are especially well represented (compared to the mean) in "health, education, and welfare" and "labour and demographic economics".
It would be interesting to see how, say, health economists view employer-provided health insurance rules.
Edit: ParagonProtege has provided a link to the original study. Thank you! (^_^)
Link.
Can this be reasonably explained by self-interest? Female and male economists' views are probably coloured by gender solidarity. Government jobs may be more likeable to women than men because of their recorded greater risk aversion. Regardless of the reason government jobs are more important for women than for men. Also in the US where the study was done middle class white women benefit quit a bit from affirmative action in government hiring.
Politics is the mind-killer probably does play a role in explaining the difference.
First two points are somewhat congruent with stereotypes. Anyone who has run into the frequent iSteve commenter "Whiskey" will probably note that the third point indicates women may not hate hate HATE lower and middle class beta males in this case.
This seems plausible since politics is about applause lights after all, the tribes are what matters not the particular shape of their attire. But might value differences still be behind the gender difference? Maybe some failed utopias I recall reading aren't really failed.
Somehow I think this does not include ideological diversity.
No mystery here. (^_^)