[Bill Gates] wanted me to stay working at Microsoft, but I didn't think he could be CEO and we could have the family life that we both had growing up, which is what we envisioned. I knew I would go back to work at some point later to some profession. I just didn't know what.

It's important to remember that behind every data point is a daughter, a mother, a sister—a person with hopes and dreams.

Now, as smartphones are coming up, there are all kinds of apps that will start to be developed that will help women.

Bill [Gates] and I believe philanthropy can only be effective if it starts things and proves whether they actually work or not. That's the place that governments often don't want to, or can't, work.

We also look at farming. Are we making sure that we're getting the latest seeds out to women so they can get a bigger yield off of their farms? A new type of seed that gets out to a man, let's say, that's drought resistant - because, of course, the rains are changing in Africa with climate change - if you don't put it in the hands of a woman, she won't necessarily get it. We look at breaking down all those barriers.

If you want to lift up an economy in Africa, you basically start with the women.

What great changes have not been ambitious?