How the height predictor works
The mid-parental formula
Add both parents' heights, add 5 inches for a boy or subtract 5 for a girl, divide by two — the result is the population-median prediction, with roughly 95% of children landing within ±3.5 inches. It encodes a real genetic signal (height is ~80% heritable) while honestly pricing the ~20% environmental plus recombination noise.
Where predictions miss
Very short or tall parents (regression toward the mean pulls children slightly toward the population middle), pubertal timing (early bloomers vs late growers can differ 4+ inches at any age before settling), and medical conditions (celiac, hormonal issues, chronic disease) all shift outcomes. The prediction is a context tool, not a ceiling or a floor.
How to use it without weaponizing it
The useful question is never "will my child be tall" but "is my child growing consistently within their genetic band." Tracking well inside the mid-parental range at any age is reassuring regardless of which percentile the child occupies. The prediction turns family height anxiety into a checkable boundary — and then it should retire to the drawer.