Why girls are usually heavier than boys at age 12?

At age 12, girls often experience earlier growth spurts due to the onset of puberty, leading to increased body fat and weight gain associated with physical development. Hormonal changes during this time can also contribute to differences in body composition. Additionally, girls may have a higher percentage of body fat compared to boys, who tend to gain more muscle mass as they approach adolescence. These biological factors can result in girls being heavier than boys at this age.