Dear Editor,
Sex determination is one of the most fundamental develop-ment processes,as gender is the first and most important identity of human.In most mammals,biological sex is determined by differences in sex chromosomes,1 while the autosomes are identical in both male and female.During the past 30 years,two genetic pathways of sex determination have been revealed in mammals:the testis-determining (SRY-SOX9-FGF9) and ovary-promoting (RSPO1-WNT/β-catenin-FOXL2)pathways.