If you're the parent of the shortest—or the tallest—kid in the class, you probably understand the fixation about childhood height. Indeed, the emphasis is first placed on size moments after your child is born, when doctors measure his height and weight. From then on, the pediatrician will measure him at every check-up. But while inches and pounds are important indicators of health, your child’s growth is really key.
"We don't worry as long as a child grows steadily, but an unusual jump in height or a sudden falloff in growth can be a sign of a health problem," says Elizabeth Littlejohn, M.D., a pediatric endocrinologist at the University of Chicago Comer Children's Hospital.
But what is “short” and what is “tall” when it comes to children, and how can you determine if his stature is healthy? We spoke with experts about average height and whether it matters in the long run.
What is Average Height?
During his first year of life, your baby grows up to 10 inches in length. However, his early size isn't very predictive of his final height or weight. He'll add about five inches during his second year, and then starting at age 3, he'll grow about 2.5 inches per year until a final growth spurt kicks in during puberty.
Here are the average heights for each gender:
Average Female Height: Females reach their adult height around age 15, and the average girl height is 5'4" in America.
Average Male Height: Boys don't top out until 16 or 17, with the average male height being 5'9".
A school-age child who falls below the 5th percentile for height is considered to be of "short stature," a clinical term meaning he's shorter than 95 percent of kids his age and gender. On the other hand, a child who's in the 95th percentile is taller than all but a few of her peers. Average height is anywhere between the 40th and 60th percentiles.
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What is “Short” for a Child?
"Short" is a descriptive term for a person whose height is considered significantly below the normal range of measurements for that age, gender, racial group, or family. Short stature is also a statistical term, generally referring to people who are shorter than 95 percent of those their age with the same sex. Thus, in any population, nearly 5 percent of people will meet this statistical definition, most with no discernible medical abnormality.
Many children who are short for their age will be normal in height as adults and have no disorder other than some delay in the timing of their growth. However, there are a variety of medical conditions that can also stunt growth and result in short stature. These include chronic illness affecting the heart, lungs, intestines or kidneys; inadequate nutrition; significant psychosocial stress; and genetic disorders like Turner's syndrome.
If your child is below the 5th percentile in height, he could also be deficient in growth hormone (GH), which affects about one in 3,500 children. Doctors can prescribe a synthetic version to promote growth in children whose bodies don't produce enough of the hormone naturally or who suffer from certain diseases that impede growth. GH won't make basketball stars out of short kids, but it can help an abnormally small child gain some height.
What if a child is short but otherwise healthy? Most doctors won't prescribe GH to kids who are not hormone deficient, but new research suggests it could add up to two inches to a healthy child's final height. The growth comes at a high price, however. GH involves daily injections and can cost about $20,000 a year. Side effects are rare and may include ear infections, muscle or joint pain, headaches, nausea, breast growth, and skin rashes. For more information, visit the Human Growth Foundation at hgfound.org or the Magic Foundation at magicfoundation.org.
And here’s some good for worried parents: People often presume that short kids—especially boys—aren't as popular as tall kids and are often teased, bullied, or depressed about their size. However, one study of almost 1,000 middle- and high-schoolers found that height made little difference in how much classmates like each other. "Short kids tend to be well-adjusted and to have just as many friends as taller classmates," says study author David E. Sandberg, PhD, a pediatric psychologist at the University of Michigan Medical School, in Ann Arbor. "If these older kids are faring okay at a time when height differences are most noticeable and bullying is more of an issue, then younger kids who are short are probably fine too."
What is “Tall” for a Child?
Just like shortness, a tall stature often results from genetics; tall parents are likely to produce a tall child. A child considered statistically tall rises above the majority of his peers.
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Tall kids might seem to be on top of the world, but height has its downsides too. Because they look older than their years, adults—and even peers—often expect them to behave more maturely. Experts also speculate that tall boys and girls have higher testosterone levels, which can contribute to aggressive behavior. Indeed, a study at the University of Southern California found that both boys and girls who stand a mere half-inch taller than their peers at age 3 tend to be more aggressive by age 11.
How Tall Will My Child Be?
Kids come in all shapes: tall or short, round or pencil thin. And while height is determined by a variety of factors—like genetics, nutrition, medical conditions, and sleep—you can generally predict how tall your child will be.
Boy Height Predictor: Add five inches to the mother's height for the minimum, and keep the father’s height the same for the maximum. For example, a male child with a 5'2" mother and 6'1" father will likely be between 5'7" and 6'1".
Girl Height Predictor: Keep the mother’s height the same for the minimum, and subtract five inches from the father’s stature for the maximum. A daughter with the same parents as above (5'2" mother and 6'1" father ) will likely be between 5'2" and 5'8".
Does My Child’s Height Matter?
Height perception is influenced by a wide variety of factors, such as culture, gender, family background, and psychological state. Although parents sometimes worry if their child is the "right" size in comparison to her classmates, the more important question is whether your child is continuing to grow at a normal rate. If your child's doctor suspects a problem—such as a growth rate that had been proceeding normally but has recently flattened—he or she may track your child's measurements carefully over several months to determine whether the growth pattern suggests a possible health problem or is just a variation of normal.
Remember that children whose parents are relatively short will probably find themselves in the lower portions of the growth charts throughout their lives—and vice versa for children of tall parents.