a vasectomy
There are a number of causes of sterility, including:
Inherited genes - Abnormalities in the Y-chromosome can cause sterility.
Physical impairments - Tubes carrying sperm can become blocked by scar tissue or infection or be missing at birth.
Disease - Illnesses, such as cancer, tuberculosis, mumps, or diabetes, can lower sperm counts.
Environment - Being exposed to excessive heat, microwaves, or pesticides.
Cancer treatments - Permanent or temporary sterility may result from some types of cancer treatments (chemotherapy, radiation, and surgery).
Other factors include hormonal imbalance, age, and lifestyle, including obesity, smoking, heavy alcohol use, and taking anabolic steroids.