Background: The key enzyme of estrogen biosynthesis, aromatase cytochrome P450,is encoded by the CYP19 gene.CYP19 plays an important role in the development,function,an regulation of the female reproduction cycle. Thus, it is the potential candidate gene affecting fertility performance in human. CYP19 transcripts are expressed mainly in the ovary,testes,breast,adipose tissue and brain. Tissue e...