How much does the heaviest 15-year-old girl or boy in world weigh?

According to multiple sources, including Guinness World Records, the heaviest 15-year-old girl in the world is Rosalie Bradford from the United States. She weighed 512 pounds (232 kg) at the age of 15.

On the other hand, the title for the heaviest 15-year-old boy in the world is not explicitly mentioned in the Guinness World Records. There may have been individuals who held the title in the past, but records can change and break over time. It's important to note that information can change, and it's always a good idea to refer to the latest verified sources for the most accurate and up-to-date information.