Onset of the release of spermatozoa (Spermarche) in Chinese male youth

Data on the prevalence of the first ejaculating emission for 83,902 Chinese boys 9 through 18 years were collected using interviews. Median spermarche al ages (MSAs) were calculated by using the status quo data and probit anal ysis. Subjects consisted of 61,812 Han boys from urban and rural areas in 2 9 provinces, and 22,090 minority boys from 17 minority ethnic groups. Media n spermarcheal ages were 14.24 years for urban Han boys and 14.85 years for rural Han boys, and ranged from 13.46 to 16.32 years for the 17 minority e thnic groups. The differences in MSAs between urban and rural Han boys in e ach province were significant and the correlation between MSA of urban and rural boys in each province was high (r = 0.83, P < 0.001). For both urban and rural Han boys, there were significant geographic variations. MSAs of b oys living in north China were generally higher than those living in the so uth, while those living in the west were higher than those living in the ea st. Variation in MSA may be related to ecological conditions in the Chinese Han populations. The different estimates of spermarcheal ages with two app roaches, periodical urine sample analysis vs. interview, and their effect o n estimating male puberty are discussed. (C) Wiley-Liss, Inc.