When I started at Partners in Health 12 years ago, there were only two full-time doctors, Paul Farmer and Jim Kim. Our focus is to deliver quality health care in poor communities.

Today, we have a staff of 11,000 with 200 doctors. We're working in 52 public facilities throughout the world.

I spent most of my time on the road, though I've cut back since having my son, Che. Now it's more like 20 percent. I'm a single mom, and so I try to bring Che with me.

For the first four years Che went everywhere with me, and for the first 18 months I did it all by myself. I'd write my team in whatever country and say, "Please find me a babysitter I'll be here these dates."

By the time Che was 18 months, I realized he needed a regular babysitter, something else constant in his life besides me. So now we have one babysitter who travels with us. He started preschool last September, so we don't travel as much, though I still take him out of school a little.

Che has been to 26 countries. He's been to Haiti nine times. He took his first steps in the mountains of Lesotho.

Che is gaining from being with me. It's important to be with your parent.

My son is learning to be empathetic. He'll tell me, "Isn't it sad that some people don't have enough to eat."

I tell Che about the work I do. He once said, "I do human rights. I try to make sure everyone is nice to each other and fair." Another time, he heard the Beatles' "All You Need Is Love" and he said, "Mommy, that isn't true. You also need health care, a house and food."

I hate traveling without him. The biggest challenge on a very personal level has been the earthquake in Haiti, because I cannot take Che there now. It has been so painful, and meant several weeks where I wasn't with him.

My son loves Diego [the Nickelodeon character], an animal rescuer, so he said, "If you get me a rescue jacket like Diego, I could go to Haiti with you."

Someone asked, "Do you feel guilty doing this with a kid?" If I had a primary-care clinic I'd have far less time with Che. I'd get home exhausted at 7:30 and have to go to work at 8 a..m. 

I am so moved by injustices. I want Che to understand that there is injustice and that you can do something about it. I want him to feel part of a world that is hopeful and optimistic, but that needs us to work on it.