Diabetes and male fertility disorders.

Couple infertility is a common condition, defined as being unable to conceive after 12 months of regular unprotected sexual intercourse. Male Factor Infertility (MFI) is responsible, alone or in combination with female factors, for about half of the overall cases of couple infertility. MFI is gradually increasing in prevalence, with a notable decline in semen parameters over the last decades. The aetiologies behind the finding of decreasing sperm counts are difficult to pinpoint but might be due in part to increasing rates of overweight and obesity in men of childbearing age. Diabetes mellitus (DM) is a common and chronic metabolic disease, whose prevalence is also gradually increasing, rising up to 10% of the population. The International Diabetes Federation estimates that there are currently more than 500 million people living with DM worldwide, the vast majority of whom suffering from type 2 DM (T2DM). There is growing awareness of the relationship between unhealthy lifestyle, in particular unhealthy diet, and MFI. Starting from all these premises, the aim of this narrative review is to describe the current evidence on the link between DM and MFI, both in terms of DM as a cause of/a risk factor for MFI and of MFI as a possible predictive marker for T2DM. Finally, we will discuss the risk of DM as a consequence of the therapy of MFI or assisted reproductive techniques.