The glutathione-S-transferase gene polymorphisms (GSTM1 and GSTT1) and idiopathic male infertility risk: A meta-analysis

► The GSTM1 null genotype was associated with an increased male infertility risk. ► Increased risk of oligoasthenoteratozoospermia was found in GSTM1 null genotype. ► Neither GSTM1 nor GSTT1 deletion was a risk factor of infertility in Asians. ► Neither GSTM1 nor GSTT1 deletion was a risk factor of infertility in Europeans. ► No association was observed between GSTT1 null genotype and male infertility risk.