As a woman finds economic opportunity, even if she's only earning a couple of dollars a day, if she can save it on her phone, she then makes different decisions for her household than her husband might.

When I studied computer science at Duke University in the first half of the 1980s, I had professors who treated women differently than men. I kind of got used to it. At Microsoft, I had to use my elbows and make sure I spoke up at the table, but it was an incredibly meritocratic place. Outside, in the industry, I would feel the sexism. I'd walk into a room and until I proved my worth, everyone would assume that the guy presenting with me had credibility and I didn't.

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.

You are indebted to life until you help some less fortunate person, just as you were helped.

If you ask, who has the chance to move into the city and get a good job out in the developing world? It's a man. Who's left to care for the kids back at home? The woman is.

In different places you run into myths around vaccination or around family planning. In the United States, one of the myths that existed for a long time, that has been completely debunked, was that autism was linked to a vaccine.

Women are the centre of the family. It's the woman who decides what's eaten in the house, when to have the kids vaccinated; everything that has to do with the children's health revolves around her.