According to WealthInsight.com, female billionaires are on the rise. The world’s youngest billionaire is a Chinese woman Perenna Kei — she’s 24. Kei is the owner of 85% of the Chinese real estate firm Logan Property Holdings. There are 172 female billionaires in the world and the wealthiest female billionaire in the United States is Christy Walton who has a net worth of $36.7B. She is the widow of John Walton whose father founded Walmart.