Obese men have reduced fertility levels, which could be caused by changes in the body's metabolism due to an excess of body fat. Some mechanisms to this occurrence have been suggested. The major ones include:
- High temperatures in the scrotum due to the insulating action of the excess fat, may cause damage to the sperm cells, thereby impairing production of sperm and also causing them to die off. Production of sperm cells takes place at temperature lower than the physiological, and that's why the scrotum is outside the body.
- Estrogen (female hormone) is produced more by the fatty tissues. This lowers the levels of testosterone (male hormone) available for stimulating the production of sperm, and may also cause erectile dysfunction.
- Leptin, a substance produced by fat cells, could cause damage to sperm cells or the cells that produce them.
- Glucose, a molecule that has increased levels in people who are overweight, has a negative effect on sperm production and motility
Although infertility related to obesity remains an area of concern to many, the prognosis for recovering from infertility by losing weight is good.