AbstractBiasness selection during talent identification program in sports may occurred due to the chronological age system applied nowadays. The aim of this study is to recognize pattern on anthropometric and fitness components relative birth-month quartiles among studied population. A total of 39372 boys (aged 7.36 ± 0.29 year) and 33723 girls aged (7.34 ± 0.29 year) were classified into four chronological birth-month groups which is first quartile (Q1 - Jan to March), second quartile (Q2-Apr to June), third quartile (Q3 - July to Sept) and fourth quartile (Q4 - Oct to Dec) involved in this study. Multiple analysis of variance (MANOVA) revealed significant difference of F(18,111336), p < 0.0001, p < 0.05 and F (18, 95358), p-value < 0.0001, alpha=0.05 between four birth-month quartiles for boy and girl participants, respectively. Tukey (HSD) follow up test of analysis of variance revealed that studied population are significantly difference in body weight, standing height, explosive leg pow.....