The research comprised a door-to-door fundraising field experiment that included 5,000 households. Each was asked to support a charity, some through buying a lottery ticket and others by giving a donation. The study found the sale of lottery tickets was the most effective way to raise money.
However, the researchers also looked at the impact of the fundraiser and found the biggest factor in determining financial success was their attractiveness (especially if they were female).
Each fundraiser was rated in terms of attractiveness on a scale of one to ten. It was found that one standard deviation unit increase in attractiveness boosted the average gift size by between 50% and 135%.
In short, beautiful women raised most money (and yes, most of the increase in income came from men).
You can download the paper here (PDF) to see some rather complicated equations showing the impact of a pretty face.