"We certainly hope that at some point in their lives they are giving back, and they know that," she said. "But that will come later. They first need to figure out who they are and what they want to do."
If her children remember one piece of her advice, one thing that she has told them, what would it be?
Gates paused, turned to look out the window and thought for a moment.
"Well, I guess, you know, be kind to other people," she finally said. "Always find that place inside of other people where you can connect. I think that's something that we talk about a lot in our home and live out. Kindness and respect."
She and Jennifer spent one vacation living with a family in Malawi, a trip Gates will repeat with her son later this year.
Phoebe and a friend will spend two weeks teaching at a preschool in Rwanda.
But Gates has also taken Phoebe to a Meghan Trainor concert in Portland, Ore. And last fall, the whole family went to see Katy Perry.
"It was supposed to be Phoebe's birthday gift, but then Jen wanted to go and Rory wanted to go and Bill's like, 'Well, I'll go.'"
Hang on, Bill Gates at a Katy Perry concert?
"Yes! It was fun."