Mark Zuckerberg with his daughter Max
Mark Zuckerberg with his daughter Max Mark Zuckerberg's Facebook page

In a Facebook post on Friday, Facebook CEO Mark Zuckerberg wrote about how he and his non-Jewish wife Priscilla Chan remind their children of their Jewish heritage.

Judaism is matrilineal, and Zuckerberg's children are not Jewish. The marriage is included in the nearly 80% statistic for intermarriage of non-Orthodox American Jews, putting the future of American Jewry on a downward spiral mitigated only slightly by the growing number of observant Jews.

"For Shabbat (Sabbath) tonight, we gave Max a kiddush cup that has been in our family for almost 100 years," Zuckerberg wrote.

"Her great-great-grandfather Max got it after our family immigrated here and it has been passed down through our family ever since."

Zuckerberg, whose wife recently gave birth to a second daughter, will take two months of paternity leave.