Predicted Adult Height Based on Parental Heights
For a boy, the predicted adult height is approximately 164 cm (range 154-174 cm), and for a girl, approximately 151 cm (range 141-161 cm), using the standard Tanner formula based on mid-parental height. 1
Calculation Methods
The Tanner formula is the standard approach for calculating genetic target height 2:
For Boys:
- (Mother's height + Father's height + 13) ÷ 2
- (155 + 160 + 13) ÷ 2 = 164 cm 2
- The typical range is ±10 cm, giving 154-174 cm 1
For Girls:
- (Mother's height + Father's height - 13) ÷ 2
- (155 + 160 - 13) ÷ 2 = 151 cm 2
- The typical range is ±10 cm, giving 141-161 cm 1
Alternative Calculation: Molinari Formula
An alternative method accounts for secular trends across generations 2:
For Boys:
- (Mother's height + Father's height + 10) ÷ 2
- (155 + 160 + 10) ÷ 2 = 162.5 cm
For Girls:
- (Mother's height + Father's height - 26) ÷ 2
- (155 + 160 - 26) ÷ 2 = 144.5 cm
The Molinari formula assumes a secular trend of 3.8 cm across generations, meaning children tend to be taller than their parents 2.
Important Clinical Considerations
These predictions assume both parents are healthy without chronic diseases affecting growth, the child has no underlying medical conditions, and normal nutrition and metabolic status throughout childhood. 1
Key Caveats:
For children with very short parents (mid-parental height below 163 cm), the Tanner method may underestimate adult height by up to 6 cm, while alternative linear regression models may only underestimate by 2 cm 3
Serial growth measurements plotted over time are more valuable than single predictions to assess if the child is tracking appropriately toward their genetic potential 1
Consider evaluation for growth disorders if the child's actual height deviates significantly from predicted target height, particularly if growth velocity is abnormal for age 1
Accuracy of Predictions:
The 95% prediction interval is approximately ±8-10 cm for most ages, meaning the actual adult height will fall within this range 95% of the time 3, 4
Predictions become more accurate as the child approaches puberty, especially when bone age and height velocity data are incorporated 5, 4
Bone age assessment (radiography of the left wrist) is the standard approach for assessing a child's remaining growth potential and can improve prediction accuracy 2
Clinical Application
Given these parental heights (mother 155 cm, father 160 cm), both parents are below average height for adults, which places the child at risk for shorter stature 3. However, children with short parents typically achieve adult heights that are taller than their parents due to improved nutrition and healthcare across generations 3, 6.