It has been found that male weight gain might lead to hormonaldisorders affecting sex hormone-binding globulin and decreasing testosterone levels.Since free testosterone and follicular stimulating hormone bear direct impact onspermatogenesis, and once both hormones are slightly affected by obesity, it isplausible to think that semen parameters may be altered in this subgroup of patients(MacDonald et al., 2010;Håkonsen et al.,2011; Teerds et al.,2011). The gene discussed is SHBG; the disease is obesity due to melanocortin 4 receptor deficiency.