Mayer and husband Zachary Bogue also have three-year-old son Macallister, with whom Mayer was pregnant when she accepted the Yahoo chief position in 2012. She announced her recent pregnancy on Tumblr in September, writing "the twins part was quite a surprise, because I have no family history of twins or any other predisposing factors. However, as I've now learned, identical twins occur by random chance in roughly 1 out of approximately every 300 pregnancies. Zack and I have embraced the surprise and are very excited about these new additions to our family."
Marissa Mayer, former Yahoo CEO
Yahoo CEO Marissa Mayer welcomes twin daughters
Marissa Mayer, president and chief executive officer of Yahoo! Inc., speaks during the 2015 Fortune Global Forum in San Francisco, California, U.S., on Tuesday, Nov. 3, 2015. The forum gathers Global 500 CEO's and innovators, builders, and technologists from some of the most dynamic, emerging companies all over the world to facilitate relationship building at the highest levels. Photographer: David Paul Morris/Bloomberg via Getty Images
Marissa Mayer, president and chief executive officer at Yahoo! Inc., smiles during the 2015 Bloomberg Technology Conference in San Francisco, California, U.S., on Tuesday, June 16, 2015. Mayer said that the company's spinoff of its stake in Alibaba Group Holding Ltd. is proceeding as planned. Photographer: David Paul Morris/Bloomberg via Getty Images
NEW YORK, NY - MAY 04: Marissa Mayer, President and CEO of Yahoo attends 'China: Through The Looking Glass' Costume Institute Benefit Gala - Press Preview at Metropolitan Museum of Art on May 4, 2015 in New York City. (Photo by Bennett Raglin/WireImage)
NEW YORK, NY - APRIL 27: Yahoo CEO Marissa Mayer attends the 2015 Yahoo Digital Content NewFronts at Avery Fisher Hall on April 27, 2015 in New York City. (Photo by Cindy Ord/Getty Images for Yahoo)
Marissa Mayer, president and chief executive officer at Yahoo! Inc., smiles during a press conference at the Yahoo! Inc. Mobile Developer Conference in San Francisco, California, U.S., on Thursday, Feb. 19, 2015. Mayer unveiled a suite of development tools for mobile applications that integrate its own advertising services with features it acquired with analytics startup Flurry Inc. Photographer: David Paul Morris/Bloomberg via Getty Images
Marissa Mayer, chief executive officer of Yahoo! Inc., listens during a panel session on day four of the World Economic Forum (WEF) in Davos, Switzerland, on Saturday, Jan. 25, 2014. World leaders, influential executives, bankers and policy makers attend the 44th annual meeting of the World Economic Forum in Davos, the five day event runs from Jan. 22-25. Photographer: Jason Alden/Bloomberg via Getty Images
Yahoo CEO Marissa Mayer speaks during her keynote address at the 2014 International CES in Las Vegas, Nevada, January 7, 2014. AFP PHOTO / ROBYN BECK (Photo credit should read ROBYN BECK/AFP/Getty Images)
Marissa Mayer, president and chief executive officer of Yahoo! Inc., reacts during the DreamForce Conference in San Francisco, California, U.S., on Tuesday, Nov. 19, 2013. Yahoo boosted its stock-buyback plan by $5 billion, returning more cash to shareholders as Mayer seeks to revive growth at the largest U.S. Internet portal. Photographer: David Paul Morris/Bloomberg via Getty Images
Marissa Mayer, chief executive officer of Yahoo! Inc., smiles at the TechCrunch Disrupt SF 2013 conference in San Francisco, California, U.S., on Wednesday, Sept. 11, 2013. Yahoo! Mayer said the Web portal has surpassed 800 million active monthly users, a 20 percent increase since she joined the company in July 2012. Photographer: David Paul Morris/Bloomberg via Getty Images
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Mayer also noted in September that she planned to approach the pregnancy similar to that of her first pregnancy by "taking limited time away and working throughout." That decision came as investors placed mounting pressure on Mayer and the Yahoo board to turn around the beleaguered tech company as it prepared to spin off its shares in Alibaba Group.
The news of the births comes just one day after Mayer held an early morning conference call with investors to inform them that the company would not spin off its take in the Chinese e-commerce giant and would instead explore a spin off of its core businesses.
Another closely watched tech executive also recently announced that his family had grown. Facebook CEO Mark Zuckerberg said Dec. 1 that he and wife Priscilla Chan had welcome a baby girl, Max. He used the birth of his daughter also to reveal that he and Chan would give 99 percent of their Facebook shares to the newly created Chan Zuckerberg Initiative, which would focus on "advancing human potential and promoting equality."