"Priscilla and I are happy to share we're expecting another baby girl!" Zuckerberg wrote on Facebook Thursday. "After our difficult experience having Max, we weren't sure what to expect or whether we'd be able to have another child."
The couple's daughter turned 1 just this past November. They had announced Chan's pregnancy with her in December 2015, saying they had been trying to conceive for a couple of years and she had experienced three miscarriages before becoming pregnant with Max.
"When Priscilla and I first found out she was pregnant again, our first hope was that the child would be healthy," Zuckerberg wrote Thursday. "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 said he grew up with three sisters who taught him how to "learn from smart, strong women," while his wife also has two sisters. Neither have brothers. He included childhood pics of the two with their sisters.
"They weren't just my sisters but some of my best friends," he said. "They've gone on to write books, excel at performance, music, sports, cooking and their careers. They showed me how to compete and still laugh together afterwards. Priscilla grew up with two sisters and they taught her the importance of family, caring for others and hard work. They supported each other as first generation college students and in their careers in medicine and business. They have so many inside jokes—the kind only siblings can understand. 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 said.