Most parents or guardians keep detailed notes of how their child is growing. I have known some to keep the information in their head, some track it on the door frame, others keep the information in a spreadsheet and some put it in their scrap books. Which ever the technique, all of them know when growth spurts happened and when they grew the most, but all of them wonder how tall they will reach when the child gets to adulthood.
Doctors also keep track of height, weight and other measurements so that they will be able to better monitor a child's growth patterns and to address any concerns if they should arise. All of the measurements are recorded on charts that show how a child is growing in comparison to other child of the same age and sex. Many factors can inhibit the growth of a child and thus affect the total height that they can reach in adulthood. Nutrition, health, gender, and genes greatly influence growth.
To determine how tall one will be can not found with absolute certainty. Though there are a few ways for estimating this measurement. A bone age X-ray, the Khamis-Roche method, and a non-scientific theory from an old wives tale are the most widely used tools for establishing the height a child will reach as an adult.
The most technical tool used to examine a child's growth is to have x-rays taken of the hand and wrist. This method is used to determine that skeletal age of the patient. A radiologist will have to study the x-ray. Comparisons are then made to others of the same sex and age to determine the ultimate height that can be reached. This method has been known to be able to come to conclusions with the least amount of error.
The Khamis-Roche method includes the gender and age of a child, the height and weight at that age and the height of both parents. The formula used to make such a calculation also takes into account the law of averages. The outcome is not exactly precise but has been know to come close to the actual height of the groups that have been studied.
Old wives tales have been told and retold throughout generations mainly starting with homemakers. Hence the name of old wives tale. The tale concerning the maximum height of a child states that taking the height of a child at certain age and to double it will determine how tall they will be as adults. There are a few versions being told and they vary with the age of 2, 2 , or 3 years old and even the gender.
Gender and age are known factors used in most calculations to determine ones height as an adult. All methods come up with conclusions that are estimates and are still influenced by nutrition and underlying health issues. Though this information can used in fun doctors should always be consulted if there are any concerns about a child's health.
(Khamis HJ, Roche AF. "Predicting adult stature without using skeletal age: the Khamis-Roche method." Pediatrics. Vol. 94. Oct. 1994 ):504-7.)