SAN FRANCISCO — It's a girl (again)! Mark Zuckerberg and wife, Dr. Priscilla Chan, are expecting their second child.

The Facebook CEO made the announcement on his Facebook page. It came the day after International Women's Day.

"After our difficult experience having Max, we weren't sure what to expect or whether we'd be able to have another child. When Priscilla and I first found out she was pregnant again, our first hope was that the child would be healthy. My next hope was that it would be a girl. I cannot think of a greater gift than having a sister and I'm so happy Max and our new child will have each other," Zuckerberg wrote.

Zuckerberg has three sisters and Chan has two.

"We are all better people because of the strong women in our lives — sisters, mothers and friends. We can't wait to welcome our new little one and do our best to raise another strong woman."

Zuckerberg and Chan, both 32, have been open about the challenges they faced in becoming parents. Zuckerberg and Chan revealed they had three miscarriages, break the silence around miscarriages and prompting an outpouring of similar stories from families. Their daughter Max is now 15 months old.

When Zuckerberg announced Chan had given birth to their first child in December 2015, he also made another blockbuster pledge: That tech's power couple would give away most of their fortune. Since then, the Chan Zuckerberg Initiative has made some big bets, such as dedicating $3 billion to curing disease.