Sex differences in the secular changes in pubertal maturation

Objective. It is a common experience among pediatricians in the industriali zed countries that many girls-but many fewer boys-present with secondary se x characteristics at a younger age than normal. This study examines whether there are sex differences in the secular changes toward earlier pubertal m aturation. Methods. The author collected the growth data from various studies performe d in Greece in the 20th century (from 1928 to 1995) and estimated the age a t peak annual height increment in each study by calculating mean increase i n height in each successive year. Results. In all studies, boys presented peak mean annual height increment a t 13 to 14 years of age. Girls did not present a discernible peak height in crement until the late 1960s; however, thereafter they presented a peak hei ght increment at 11 to 12 years of age. Conclusions. The data suggest sex differences in the secular changes in pub ertal maturation, girls being affected more intensely than boys.