The latest children's growth charts (there are separate ones for boys and girls) were created by the Centers for Disease Control (CDC) based on years of data collected from thousands of children. Last updated in the year 2000, the tables track the growth of healthy kids from birth to 20 years by recording height, weight, and head circumference. The tables also list BMI (body mass index), a number that evaluates a child's weight in relation to height, for kids age 2 and up.
The purpose of the charts isn't to compare your child with others -- generally, any weight or height between the 5th and 95th percentiles is considered normal. Instead, pediatricians use the stats as a reference point to monitor the rate at which your child grows over time. When a doctor analyzes your child's chart, she's looking for a consistent pattern of growth, which is one way to tell that your child is healthy. In fact, a baby who starts out in the 5th percentile and stays there steadily for years can be considered healthy as long as he continues to grow, whereas a child who starts out in the 50th percentile and drops to the 30th could have a development problem. --Cammie McGovern
Originally published in the June 2001 issue of Parents magazine. Updated 2009.