Several studies showed that in men basal FSH levels and FSH response to LH-RH correlated well with the sperm production.12–16 An increased FSH response to LH-RH can be the first manifestation of testicular damage15, although normal FSH levels do not rule out the possibility of azoospermia.14,17,18 In our study semen analyses in 6 patients with a high basal FSH level showed azoospermia. This evidence concerns the gene GNRH1 and Azoospermia.