The average 12-year-old boy in the United States is 58 inches tall and weighs 90 pounds, according to the Centers for Disease Control and Prevention. 12-year-old girls in the United States have a very similar average height and weight, at 59 inches and 93 pounds on average.
Between their third birthday and the beginning of puberty, children grow an average of two inches per year. The growth rate of both male and female children, however, can be highly variable. While some children grow at a basically steady rate from childhood until puberty, most children experience growth spurts, during which their growth rate increases for a short period of time.
Genetics plays an important role in both a child’s rate of growth and height. The rate at which a child grows is largely dependent on genes inherited from their biological parents. If one or both parents are taller than average, it is more likely that their children will also be taller than average.
Puberty’s Effect on Growth
At the age of 12, many children have already begun to go through puberty. During the 2 to 5 years a child is in puberty, their growth rate usually increases dramatically, up to four inches per year. Girls usually enter puberty slightly before boys, which is why 12-year-old girls are on average one inch taller than 12-year-old boys. Girls enter puberty on average between the ages of 8 and 13, while boys enter puberty on average between the ages of 9 and 15.
Parents who are worried that their child’s growth is abnormal in some way are encouraged to schedule regular checkups with their child’s doctor. A doctor will monitor the height and weight of the child, note any irregularities, and communicate with parents about their child’s growth. In some cases, a child’s doctor may refer the child to a pediatric endocrinologist, a doctor who specializes in growth disorders.
Encouraging Normal Growth
Lifestyle choices during childhood can also have an effect on the growth rates of children. Getting enough sleep, eating healthy meals, and exercising regularly are all actions that encourage healthy and normal growth in children. While all children require different amounts of sleep, the average child needs between 10 and 12 hours a night to be well rested, giving their body enough energy to grow normally. Additionally, a healthy diet and daily exercise, such as biking, rollerblading, or sports, can help children maintain a healthy weight as they continue to grow.