Some of the main causes of male infertility are previous injury to testicles, exposure to radiotherapy, drugs, and alcohol. A few genetic factors play a role and sexually transmitted diseases can also cause fertility problems.

The best way is to maintain overall good health. Exercise regularly, watch your weight, avoid tobacco, avoid excessive alcohol, and excessive caffeine.

It is usually a combination of factors that include multiple child-births, age, obesity, and smoking. Other factors that raise the risk are spinal chord injuries, chronic bladder infections, diabetes, hysterectomy, and multiple sclerosis to name a few.