Facebook co-founder Mark Zuckerberg (31) and his wife Dr Priscilla Chan (30) on Tuesday announced that they had become parents to Max, a baby girl.
Max was born about a week ago and her parents wrote an open letter to her "about the world we hope she grows up in".
"Your mother and I don't yet have the words to describe the hope you give us for the future. Your new life is full of promise, and we hope you will be happy and healthy so you can explore it fully. You've already given us a reason to reflect on the world we hope you live in," Zuckerberg said in the letter.
They also announced the formation of the Chan Zuckerberg Initiative and pledged to donate 99% of their Facebook shares, which are currently worth $45 billion, over the course of their lifetime.
"As you begin the next generation of the Chan Zuckerberg family, we also begin the Chan Zuckerberg Initiative to join people across the world to advance human potential and promote equality for all children in the next generation. Our initial areas of focus will be personalized learning, curing disease, connecting people and building strong communities.
We will give 99% of our Facebook shares -- currently about $45 billion -- during our lives to advance this mission. We know this is a small contribution compared to all the resources and talents of those already working on these issues. But we want to do what we can, working alongside many others."
The letter, which was posted by Mark on Facebook, has received thousands of comments congratulating the new parents.
Mark Zuckerberg with wife Priscilla Chan; Image source: Mark Zuckerberg/Facebook
One of the comments was by Vindu Goel, a technology reporter at The Times, who asked the couple what had prompted him "to give away so much of your fortune so early in your lifetime?"
To which Zuckerberg replied, "Two main ideas have led us to start early. First is that we have a lot to learn and giving, like anything else, takes practice to do effectively. So if we want to be good at it in 10-15 years, we should start now. Second is that any good we do will hopefully compound over time. If we can help children get a better education now then they can grow up and help others too in the time we might have otherwise waited to get started."
In July this year, while announcing that they were expecting a child, Zuckerberg shared in a public post that went viral about their experiences of trying "to have a child for a couple of years" and how they had "three miscarriages along the way".
Zuckerberg and Chan were both students at Harvard when they met at a fraternity party. The couple married nine years later in 2012, the day after Facebook's initial public offering.