Target height, or genetic target height, refers to the child’s genetic height value calculated from the height of the child’s parents. Because target height can predict the genetic potential of a child’s height, it is commonly used in clinical practice for differential diagnosis and treatment monitoring of short height in children. Children’s height is influenced by parental genetic factors such as target height, but also by environmental factors such as nutrition, exercise, sleep, mood, and disease.
Calculation method
The CMH (the Corrected Midparental Height) method, in which the average parental height of 10.5 cm is the target height for boys and the average parental height of 6.5 cm is the target height for girls, has been widely used in pediatric clinics to calculate the genetic height or target height of children based on the height of both parents.
Genetic target height for boys = (father’s height + mother’s height)/2 + 6.5 CM
Genetic target height for girls = (father’s height + mother’s height)/2 – 6.5CM
This method has been commonly used since the 1970s. The specific formula is
Boy = (father’s height + mother’s height + 13)/2 ± 8CM
Girls = (father’s height + mother’s height – 13)/2±8CM
As our standard of living has improved significantly in recent years, many of the previous generation may have not received more timely and effective treatment due to inadequate nutrition or illnesses that cause adequate height growth, and now children’s adult heights are often higher than their genetic heights. And the CMH method takes genetic factors to 100%, which is obviously unreasonable. At the same time, genetic height in recent years also found that there is a regression phenomenon, that is: both husband and wife are taller, the child genetic height will be slightly lower than the calculated, both husband and wife are shorter, genetic height will be slightly higher than the calculated. Because it is more common for taller people to find taller people to marry and shorter people to find shorter people to marry, and humans do not experience a gradual increase in height differences due to this phenomenon.
Some scholars have proposed a new way of calculating target height, FPH (the Final Height for Parental Height) method through sufficient research, which has been verified by some domestic areas and proved to be more accurate and reasonable, thus it has now replaced the CMH method mentioned earlier.
The formula of FPH method is
Boy = 45.99 + 0.78 × (father’s height + mother’s height) ÷ 2 ± 5.29 CM
Girls = 37.85 + 0.75 × (father’s height + mother’s height) ÷ 2 ± 5.29 CM
Here we need to remind you to note that
1, the calculation formula is statistically processed and derived, only about 95% of normal people are in this range, not necessarily everyone can reach.
2, the calculated median value followed by ±5.29CM, which means that it may be higher or lower than the median value.
3, genetic height is only the range of adult height that a perfectly normal person should achieve, it does not mean that all children can achieve. Never disregard your child’s growth and development because the calculated genetic height is still acceptable. From time to time, children of parents who are both taller are short, because a high parental height does not mean that the child will never have a disease such as growth hormone deficiency.
4. Those whose parents are short should not be too pessimistic. Since both parents have not undergone any examination and treatment for dwarfism in the past, it does not mean that there are definitely no diseases affecting height in the family. Some diseases can now be examined and effectively treated, and if the child also has the same disease, it is entirely possible to achieve a more ideal lifetime height through examination and treatment.
5, due to the improvement of living standards now, sex hormones in food are inevitable from time to time, and sex hormones in health care products are even more proliferated, coupled with too much stimulation of bad information, children’s development is generally advanced, and precocious sexual maturity has increased significantly. You can’t ignore your child’s development because he or she is still tall or high. When you are precocious, your height is often higher than that of your peers, but you can stop growing early, so your height may be shorter in the future. Once puberty is over, growth will stop and no more treatment is possible.
6. The most accurate way to predict adult height is through accurate assessment of bone age. Because only the parents’ height is considered when calculating genetics, it does not take into account the child’s current height and bone age at that time. If the bone age is greater than the age, the later growth space will be smaller and the adult height will be lower, while the bone age is less than the age, the later growth space will be larger and the adult height may be higher. Since bone age is the physiological age of a person, it should match with the present actual age. If the difference is too large, it is often caused by disease and requires timely examination and treatment.
7, first in Japan, and now also in Taiwan and some Western European countries, all children and adolescents in the growth period are given a free bone age film every two years, so that abnormalities in growth and development can be detected in time for timely treatment, which is worthy of reference for the country.