Serum kisspeptin levels were significantly lower in fertile men (group A) as compared to infertile men (groups B and C) regardless to semen parameters (85.18 ± 20.47 ng/dL, 109.37 ± 28.64 ng/dL, and 108.70 ± 32.30 ng/dL respectively; p = 0.019). The gene discussed is KISS1; the disease is Infertility.