Q. Are children usually taller than their parents?

A. The results vary from child to child and family to family, and depend on genes and environmental factors, especially nutrition.

Doctors often use a fairly simple formula to predict the adult height of a child based on the heights of the parents. That formula, dating from 1970 research, predicts that most (but not all) children eventually will reach a height somewhere within a fairly small range that can be estimated by the average combined height of their parents.

For boys, the formula combines the height of both parents, adds five inches (or 13 centimeters) and divides by two.

For girls, it combines the height of the parents, subtracts five inches and divides by two. A more complex formula accounts for extremes in parental height.