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.

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

Childbearing, I mean, if there's no place to go to deliver your baby, then you're the one that's delivering in those unhealthy circumstances. Or if you can't get access to family planning, your chances of surviving and being able to bring your kids up if they come one right after the other, that locks you into a cycle of poverty.

The world is full of what seem like intractable problems. Often we let that paralyze us. Instead, let is spur you to action. There are some people in the world that we can't help, but there are so many more that we can. So when you see a mother and her children suffering in another part of the world, don't look away. Look right at them. Let them break your heart, then let your empathy and your talents help you make a difference in the lives of others. Whether you volunteer every week or just a few times a year, your time and unique skills are invaluable.

Women speaking up for themselves and for those around them is the strongest force we have to change the world.

I've travelled extensively in the last 16 years - to slums in Bangladesh, to townships in South Africa, to all kinds of places in India, etc. When I would go and talk to villagers about something like vaccines, if I stayed long enough, the women would bring the conversation around and say: "What about this family planning tool? We can't keep having the number of children we're having."

If we're going to make progress on this issue [of contraception], we have to be really clear about what our agenda is. We're not talking about abortion. We're not talking about population control. What I'm talking about is giving women the power to save their lives, to save their children's lives and to give their families the best possible future.