Causes of male infertility include:
-Using steroid- this causes the testicles to shrink
thereby rendering the man infertile.
-Malnutrition and anaemia.
-Wearing tight pants and boxers- this causes
infertility by decreasing the production of sperm
due to the heat created by the tight underwear,
this heat affects the scrotum negatively.
-Lots of intense workouts- Too much of high
intense exercise is capable of rendering a man
infertile as this causes the body to produce lots
of adrenal steroid hormones, which then cause a
testosterone deficiency.
-Smoking– this significantly decreases both
sperm count and sperm cell motility, which is the
ability to move spontaneously and actively.
-A prolonged use of marijuana and other
recreational drugs.
-Chronic alcohol abuse.
-Lack of adequate vitamin C and Zinc in the diet.
The above show that male infertility depends a lot
on health, so, men who live a healthy lifestyle are
more likely to produce healthy sperm, thereby
their reducing chances of infertility.

isn't wanking part of it...

Thank you.