From the the World Bank's PSD blog:
Just what does it take to make a successful female entrepeneur in the developing world? At least part of the answer is that a woman needs a relatively effective way to save money. A new paper on Savings Constraints and Microenterprise Development reports on the results of an experiment in Kenya that provided zero-interest savings accounts to village microentreprenuers:
...formal savings accounts had substantial positive impacts on business investment for women, but no effect for men...roughly a 40% increase in average investment, four to six months after the opening of the account.
Emphasis added. Is it surprising that zero-percent interest-bearing savings accounts can have such a large effect? Perhaps, but the authors point to one possible mechanism:
..many women in developing countries face constant demands on their income (from relatives or neighbors), and it may be difficult to refuse requests for money if the cash is readily available in the house.
Of course, it's also harder to spend cash if you're not holding it in your hand, and these accounts didn't come with debit cards. Harder for the husband or child to spend it as well. Or maybe it's a purely psychological effect. Whatever it is, I'd love to see some more empirical work on this to see how well it holds up.