We [with Bill Gates] started to make decisions about what we'd invest in. Then I actually started traveling for the foundation. I've probably been to India now eight times at least and Africa numerous times.

Despite the debunking, you have a small group in the last five years that hasn't wanted to vaccinate their children, for instance, for measles. Then, all of sudden, we got an outbreak of measles and kids were starting to die from measles.

Women and girls should be able to determine their own future, no matter where they're born.

Contraceptives unlock one of the most dormant, but potentially powerful assets in development: women as decision-makers. When women have the power to make choices about their families, they tend to decide precisely what demographers, economists, and development experts recommend. They invest in the long-term human capital of their families.

Microsoft certainly makes products for the Macintosh.

Any social or cultural change has to be made openly and with people agreeing. You don't get there by just pushing an outsider's point of view.

Human-centered design. Meeting people where they are and really taking their needs and feedback into account. When you let people participate in the design process, you find that they often have ingenious ideas about what would really help them. And it’s not a onetime thing; it’s an iterative process.