**3.5 Obesity**

Despite the advances in understanding the male infertility, studies show the 30% of male infertility corresponds to idiopathic sperm abnormalities [30]. Important to mention here that a variety of conditions affect semen parameters- Medical condition like liver failure,renal diseases, cystic fibrosis, chronic obstructive pulmonary disease are few names to be mentioned here. The Medical etiologies impact fertility and therby causes the effects on hormonal levels, sexual function or testicular function and spermatogenesis. In maintaining the quality semen parameters, sexual function and fertility potential man's state of health needs to be optimized by large. Obesity is linked with male infertility primarly and mainly due to hormonal changes. Bierick et al. has come up with an inverse relationship between body mass index (BMI) and testosterone, testosterone to estradiol, ejaculate volume, sperm concentration and morphology. In this regard many authors reported higher rates of Azospermia and oligospermia among obese men compared with men of normal weight. It is also pooled in the literature that couples with a female partner of normal BMI and obese male partner are more susceptible to have prolonged time to conceive compared with couples with male partners of normal weight. Studies also bring on forth that couples with an obese male partner seeking Assisted reproductive technology (ART) have decreased pregnancy rates and increased pregnancy lost mainly because of prevalent DNA fragmentation [31].

Mass Adipose tissue in obese individuals leads to conversion of testosterone to estrogen which potentially affects the HPG axis therby causing the reduction in the release of gonadotrophin [32]. Apart from this, the raised leptin production by white adipose tissue causes the fall in testosterone production. Further studies reveal the increased scrotal adiposity as one of the major reasons of testicular heat stress and causes oxidative stress. It can potentially impair the spermatogenesis, integrity of DNA and sperm-oocyte interaction.
