"In July 2006, women accounted for just under 17% of parliamentarians worldwide. A woman was the head of government in only seven countries." This could be due to short supply, higher cost of entry due to family, or to voter attitude, which previous research has found may be "distaste" for female leadership.
Researchers at the Center for International Development at Harvard (PDF here) have found that voters, men in particular, are prejudiced against female leaders. At least those in certain villages in India, where the 73rd Amendment mandates that at least 1/3 of government positions be filled by women. This mandate allowed the researchers to study the attitude toward female leaders and how exposure to female leadership changed those attitudes.
They found that the voters in a village with its first female leader give evaluations of the woman's performance that are lower than those of her men counterparts (even when they outperform the men). However, that "distaste" dissipates over time "“ when a village is exposed a second time to a female leader, the woman's evaluations are on par with those of her male counterparts. It appears, per the research, that exposure to a female leader reduces prejudice by 50 to 100% (depending on the village).
Be sure to read more of what Diana learned today here.