Abstract: Objective To analyze the relationship between menarche or first spermatorrhea among high and primary school students and parental age at birth,and to provide a theoretical basis for early pubertal development research and health education.Methods By random stratified and cluster sampling,7 285 students(3 649 boys,3 636 girls)from two areas in Chongqing urban districts were enrolled,boys' first spermatorrhea,girls' menarche and their parental age at birth were studied.Statistics analysis system included description statistical analysis,t test,Multiple linear regression.Results Mean age of first spermatorrhea was 13.14 y,The boys in rural was 0.2 years earlier than urban(P=0.613);the average age of menarche was 12.43 years,but no significant difference between rural and urban(12.42 vs 12.45,P=0.003);there was no significant difference between maternal age at birth and menarche or first spermatorrhea.Each year increase in paternal age showed a 0.034y (Rural:0.019,P=0.024;Town:0.048 y,P=0.000) earlier onset of menarche in daughters and a 0.025 y (Rural:0.013,P=0.818;town:0.029 y,P=0.027)earlier onset of first spermatorrhea in sons.Conclusion A older paternal age at birth may be a risk factor for early first spermatorrhe,menarche of their offspring.