Boys normally develop 1-2 years later than girls, usually 11-12 years old for girls and 12-13 years old for boys. The late development of boys is influenced by multiple factors, such as family factors and diet, so it is normal for boys to develop 1-2 years later than girls. The late development of children is related to diet, disease and family. For example, diet, poor nutrition or insufficient protein intake of children will affect their growth and development. So, pay attention to give your child a balanced diet, protein, calorie balanced intake, to avoid malnutrition in children, it will not affect their development.