Human Interest Bill Gates Celebrates Daughter Phoebe's 20th Birthday with Sweet Tribute: 'I'm So Proud of You' The Stanford University student received some special birthday wishes from her father and sister By Abigail Adams Abigail Adams Instagram Twitter Digital News Writer, PEOPLE People Editorial Guidelines Published on September 14, 2022 05:19 PM Share Tweet Pin Email Trending Videos Bill Gates and daughter Phoebe. Photo: Patrick McMullan/Getty Bill Gates' youngest daughter Phoebe is turning 20! The Stanford University student received some special birthday wishes from her family on Wednesday as she celebrated the big 2-0. Bill, 66, paid tribute to his daughter on Instagram with a sweet message and adorable photo of himself with Phoebe when she was a toddler. "One of the greatest joys of my life is watching my kids grow into amazing adults," the Microsoft co-founder wrote alongside the image. "Happy Birthday, @phoebegates. I'm so proud of you." Bill Gates Donates $20 Billion to Foundation, Plans to Drop from List of World's Wealthiest People Bill Gates and daughter Phoebe. Bill Gates/Instagram Sister Jennifer Gates also honored Phoebe's birthday in an Instagram Story featuring an elegant photo of Phoebe in her bridesmaid's gown at Jennifer's October 2021 wedding. "Happy Birthday to the smart, beautiful, amazing @phoebegates," Jennifer, 26, wrote atop the photo, adding, "So proud of you." Never miss a story — sign up for PEOPLE's free weekly newsletter to get the biggest news of the week delivered to your inbox every Friday. Phoebe and Jennifer are the youngest and oldest of Bill's three children with ex-wife Melinda French Gates. (Their son Rory is 23 years old.) Earlier this summer, Melinda, 58, met up with Phoebe in London, where the two went on a series of adventures together. Phoebe posted a variety of photos from their trip on Instagram, including a Reel of her mom showing off her posing skills across the city. Bill Gates Says He Had a 'Great Marriage' to Melinda French Gates: 'I Wouldn't Have Changed It' In June, Phoebe appeared with her father Bill at the TIME 100 Gala in New York City, where they posed for father-daughter photos. The philanthropist donned a classic black tuxedo for the occasion, while his daughter sported a fashionable mesh dress. "So honored to attend #Time100 with my dad," she wrote in a social media post. "I felt so inspired by all these change-makers."