Why do the majority of micro-loans go to women?

More than 70 percent of loans go to women clients according to a paper [if the link does not work you can try the first link here] by Sugato Chakravarty, S. M. Zahid Iqbal, & Abu Zafar M. Shahriar. The abstract 

We use controlled experiments to identify the proximal causes of gender differences in the repayment of microcredit. We recruit male and female subjects from a patriarchal and a matrilineal community in Bangladesh, who live in the same villages, and find that the female subjects have a greater willingness to repay microcredit in every society irrespective of the type of loan. Thus, the observed gender differences in the repayment of microcredit cannot be explained by the different roles that women play in different societies. In other words, women are “naturally” better credit risks than men in microcredit. We confirm that our results are not driven by the common culture and values among our subjects that stem from geographical proximity. 

The title of the paper is "Are Women “Naturally” Better Credit Risks in Microcredit?  Evidence from Field Experiments in Patriarchal and Matrilineal Societies in Bangladesh." Many questions remain but culture does not seem to be the answer. 
HT: Michele Battisti