I believe that birth control and sex education in developing countries are two of the most important causes you can donate to.

Third world countries suffer from resource deficits. The deaths resulting from these deficits limit the population. Donating to charities loosens this throttle on the population. Population then grows, more people consume more resources, and the vicious cycle is perpetuated.

Therefore, since we're working to remove this natural population cap, we should be working to create an artificial one. Enter the need for birth control and the sort of sex education and/or cultural indoctrination necessary for the adoption of it.

Most, if not all, of the countries topping this 2016 fertility rate table are third world countries. Of these countries, twenty of them have fertility rates (births per woman) above five. Children are very costly - just reducing this number by one for any given family could have a huge effect on their quality of life.

Maybe this view is myopic - perhaps these countries need population growth to achieve the sort of professional specialization that enables first world economies.

I also understand that many third world inhabitants are subsistence farmers. Since children are traditionally free labor in such situations, having more children may actually be a net positive for most families (though it may or may not benefit the community as a whole).

I'd like to hear other people's opinions about this topic. Any options for charities that address this need would be great as well. :)