I'll start out very briefly. The committee on electoral reform dealt with this last summer at great length, and my impression from my colleagues' presentations was that proportional representation does not directly guarantee that more women will be elected. It might in some countries. Those are countries with a strong tradition of social democracy. In short, I would say that it's social democracy in those electoral systems that's propelling the election of women, rather than the electoral system per se.
As there are expanding numbers of democracies around the world, we're starting to see more variation in the patterns of women elected in those electoral systems.