MENLO PARK (CBS SF) – Facebook CEO Mark Zuckerberg announced on the social network Tuesday that his wife Dr. Priscilla Chan gave birth to a baby girl.

Their daughter, named Max, is the couple’s first child.

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Along with the announcement, the couple penned a lengthy letter to their daughter. In it, they pledged to give nearly all of their Facebook stock to charitable causes.

“Like all parents, we want you to grow up in a world better than ours today,” the couple wrote. “We will do our part to make this happen, not only because we love you, but also because we have a moral responsibility to all children in the next generation.”

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The couple announced the creation of the Chan Zuckerberg Initiative, which aims to “advance human potential and promote equality for all children in the next generation.”

To fund their charitable work, the couple plans to give away 99 percent of their Facebook shares, which is currently worth about $45 billion.

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The family plans to announce specific details at a later date.