“It starts with lots of phone calls to you, his other partner,” Chan said jokingly to Sandberg. “We [Chan and Zuckerberg] are complimentary and we challenge each other to think more deeply about the questions we’re faced with. We push each other in different ways, it can be uncomfortable at times but it’s a lot of fun.”

The couple launched the Chan Zuckerberg Initiative nearly a year ago, pledging up to $1 billion (in Facebook shares) over the next three years. The goal of the initiative is to “advance human potential and promote equality in areas such as health, education, scientific research and energy. One of their first projects is a new school in East Palo Alto, Calif., not far from Facebook’s Bay Area headquarters. The school aims to blend a curriculum with on-site healthcare.

“This work is incredibly important and personal to me,” said Chan, the daughter of Chinese immigrants and the first to graduate college in her family. “My parents believed in the power of education.”

Throughout her adult life, Chan has also been guided by a calling to provide healthcare for children and is a pediatrician by training, so the school merges both causes for her.

While she was a student at Harvard University, she helped run a program for kids. One of the children didn’t show up for a few days and so she went to look for her and discovered that her two front teeth were broken. “It was that moment I realized I was going to make public service central to my life,” said Chan. “At that moment I decided to go to medical school to help advocate for the lives of children.”

Chan also touched on lighter topics. Her infant daughter’s first word? Dog. What does Mark [Zuckerberg] cook? Two racks of baby back ribs (never one). And what is her advice to young women? “You are capable beyond your wildest imagination. Whatever you want to do, do it now.”