Women are more decent than men.Hmm. It's a question I've often thought about, why is it that men vastly outnumber women in politics almost everywhere in the world? frankly, I don't know for sure. But I'll try..
Fewer women than men itch to lord it over others. Also, women are less willing than men to perform the countless asinine stunts and soul-shriveling pandering necessary to win political office. [link]
It could be that the conventional wisdom is right. The world is less cosmopolitan than we comspolitians think and women in most societies are expected to stay at home, and therefore there's less of them in most professions. Political representation works on a regional basis, where there's a greater likelihood of people getting into the politics (running for public office) from non-urbanized, more traditional areas than any other profession. More traditional means, there's more of a chance that women are expected to stay home or be in more "acceptable" women-roles rather than running for public office. This results in fewer women getting into politics overall, lowering aggregates significantly.
Note that Hillary Clinton is a senator from New York, not Texas. Although Mayawati, the Chief Minister of India's Uttar Pradesh, who is also from a lower caste, is probably a counter example.
I guess it's a question for the freakonomists.