Facebook CEO Mark Zuckerberg and his wife Priscilla Chan have pledged to donate 99 percent of their Facebook shares -- about $45 billion -- to advance human potential and promote equality for children.

Declaring the "Chan Zuckerberg Initiative" as they welcomed their first girl child Maxima Chan Zuckerberg or "Max", the couple on Tuesday said they have created a new foundation that would initially focus on "personalised learning, curing disease, connecting people and building strong communities."

"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," they posted in a 2,200-word letter to their new-born daughter on Facebook.

"We will give 99 percent of our Facebook shares 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 couple wrote.

We will share more details in the coming months once we settle into our new family rhythm and return from our maternity and paternity leaves, Zuckerberg said.

In the letter to their new-born daughter, the new parents said: "Today your mother and I are committing to spend our lives doing our small part to help solve these challenges."

Zuckerberg owns about four million of Class A shares in Facebook and approximately 419 million Class B shares.

Each Class B share is worth 10 votes apiece which gives Zuckerberg majority voting power and control over Facebook's strategic direction.

"We can make progress towards these opportunities only by standing on the shoulders of experts -- our mentors, partners and many incredible people whose contributions built these fields," the letter read.

"Max, we love you and feel a great responsibility to leave the world a better place for you and all children. We wish you a life filled with the same love, hope and joy you give us. We cannot wait to see what you bring to this world," the proud parents said.

"Many of the greatest opportunities for your generation will come from giving everyone access to the internet. The internet is so important that for every 10 people who gain internet access, about one person is lifted out of poverty and about one new job is created," the letter further read.

Yet still more than half of the world's population -- over four billion people -- do not have access to the internet.

"If our generation connects them, we can lift hundreds of millions of people out of poverty. We can also help hundreds of millions of children get an education and save millions of lives by helping people avoid disease," the Facebook CEO pointed out.

Facebook currently has 1.44 billion monthly active users.