Age at spermarche and comparison of growth and performance of pre- and post-spermarcheal Chinese boys

The prevalence of first ejaculation emission (spermarche) in Chinese Han bo ys in 1995 was considered. The subjects were 86,744 Han boys 9 through 18 y ears randomly selected from 28 provinces. Median spermarcheal ages (MSAs) w ere 14.4 and 14.6 years for urban and rural boys, respectively, and 14.3, 1 4.6, and 14.7 years for the boys of 1st, 2nd, and 3rd socioeconomic classes , respectively. Two environmental factors, ecological and socioeconomic, ha d strong influence upon MSAs. Eight indicators of somatic growth and motor ability were compared between pre- and post-spermarcheal boys of the same a ge. Post-spermarcheal boys were advanced in body size, shape, and physiolog ical function during early and middle puberty, but most, of the difference disappeared by 16 years. Pre-spermarcheal boys in a given age group were mo re linear and had more potential for increasing leg length into late adoles cence. Within an age group, post-spermarcheal boys had advanced performance s in several tasks requiring endurance, strength, and power around the age of maximum growth, 13-15 years. At older ages, the groups did not differ. A m. J. Hum. Biol. 13:35-43, 2001. (C) 2001 Wiley-Liss, Inc.