Sir.—In the recent letters on early maturity and isosexual precocity, the statement was made that "the correlation of growth between girls and their parents is higher than that observed between parents and their sons."1 Actually, boys and girls are equally affected, especially with regard to maternal maturational timing.
Having investigated mother-child resemblances in maturational timing in thousands of children of both sexes, we found that maternal maturational timing is reflected in the size of boys and girls alike. Both the sons and daughters of early-maturing mothers are advanced in ossification timing and bone age and are larger through the time of maturity.2,3 If anything, the age at menarche of the mothers has more effect on the dimensional and maturational development of the sons than on the daughters.
Of equal interest and importance is the fact that the sons of early-maturing mothers are (like the daughters) fatter at