India has over 20 percent of the kids born in the world. And they move around a lot.

We got a malaria initiative, really a phenomenal time, even though in the early stages there was some uncertainty. Then of course [Barack] Obama, although he had budget constraints, he believed in these things; a lot of new initiatives, including in agriculture.

Improving the health & productivity of the poorest is one of the best investments you can make in the future of the world

I'm cooler than you. WAAAY cooler.

It is a high bar to say that it's more fun than working on software because the work at Microsoft that both Melinda [Gates] and I did was thrilling. We were making breakthroughs and empowering people.

Now, we put out a lot of carbon dioxide every year, over 26 billion tons. For each American, it's about 20 tons. For people in poor countries, it's less than one ton. It's an average of about five tons for everyone on the planet. And, somehow, we have to make changes that will bring that down to zero.

I'm not a macroeconomics person.