Until puberty starts, at around the age of 10, there isn't much difference in growth rate between boys and girls; about two inches (5 centimeters) per year. Growth rates change during puberty, when hormones start the process of physical changes in teens, which occur at different individual rates and at different ages within their gender group. Growth continues for one or two years during puberty, but males and females develop at different rates.
The onset of puberty in girls usually starts at around the age of 10. Girls on the average start their growth spurt between the ages of 10 and 14, about a year before boys. This is the reason girls are often taller than boys of the same age in early adolescence. The growth spurt in girls is also shorter than in boys. Before girls start menstruating they have already reached close to their maximum height. The period of intense growth occurs from 6 to 12 months before menstruation begins. In females, the growth in height during puberty is accompanied by an increase in hip width.
The average boy starts his growth spurt at the age of 12, and it is much more dramatic. Boys can grow four inches (10 cm) per year, but the most intense period of growth only lasts for a few months. At the end of puberty, boys are usually about five inches (13 cm) taller than girls on the average. The peak of growth is generally two years after puberty begins. In boys, the muscles also develop at this time. Genetics play a big part in growth patterns. Children usually stay in the same growth percentile over the years, which is an indication of normal individual growth rate.