SEXUAL MATURATION OF CHINESE BOYS IN HONG KONG

Abstract

Sexual maturation of 3,658 Chinese school boys from 6 to 18 years of age was assessed by investigating four attributes associated with puberty, namely, growth of genitalia (penis), pubic hair, axillary hair, and change of voice. The first two attributes were rated on a 5-point scale (5 stages), and the last two attributes were just noted as having occurred or not. The children were divided into three socioeconomic groups based on multiple criteria comprising family educational level, occupation, income, and housing conditions. The probit method of biological assay with weighting scheme was employed to estimate the 30%, 50% (median age), and 70% end points and fiducial limits of the onset of development of the above-mentioned four attributes of boys in the three socioeconomic groups and of the total sample. In the case of genitalia and pubic hair, the same was done for the completion of development. The median ages (50% end point) of onset of development for genitalia, pubic hair, voice, and axillary hair of the total sample were 13.19 ± 0.19, 13.31 ± 0.21, 13.67 ± 0.43, and 14.57 ± 0.10 respectively. The median ages (50% end point) for the completion of genitalia and pubic hair development were the same, 16.47 ± 0.10. The estimated duration between the successive developmental stages of genitalia and pubic hair show the period between Stages 2 and 3 to be the shortest (genitalia, 0.55 year, pubic hair, 0.39), and longest in the period between Stage 4 and 5 (genitalia and pubic hair, 1.87). The estimated whole duration of pubescence from onset to completion was about 3.28 years. In temporal sequence of maturation, the development of genitalia and pubic hair was the first and practically simultaneous, followed by the change of voice (0.48 year after genitalia), and the last to develop was the axillary hair (0.9 year after change of voice). The effect of socioeconomic background was shown to be evident, the boys from well-circumstanced homes being significantly more advanced in development than those from poor homes. Comparison of our results with those of similar cross-sectional investigations on American and British boys show little difference in spite of race and clime.