Secular trends for age at spermarche among Chinese boys from 11 ethnic minorities 1995–2010: a multiple cross-sectional study

摘要

ObjectivesWe compared the differences in median age at spermarche among 11 ethnic minorities in 2010, estimated the trends regarding age at spermarche in different ethnic minorities from 1995 to 2010, and explored the association of spermarche with body mass index (BMI).