Some common causes of infertility in men include:
– Hormonal imbalance.
– Smoking.
– Overheating of the testicles caused by exercise, hot water, tight clothing, excessive sitting (truck drivers) and other conditions and situations.
– Cancer medications and radiation therapy.
– Mumps after puberty.
– STIs.
– Anatomical abnormalities of the genitals such as undescended testicles.
– Use of some medications, such as some for high blood pressure, some antidepressants, and male hormones.
– Genital injury.
– Prostate surgery.
– Varicose veins in the testicles.
– Excessive alcohol.
– Intercourse problems such as premature withdrawal or poor timing with their partner’s menstrual cycle.
– Spinal cord injury.
– Genetic abnormalities.
– Urinary tract infection.
– Cystic fibrosis.
– Illicit drug use (e.g., using cocaine, smoking marijuana).
– Opiates.
– Steroids.

Some men are more prone than others to infertility problems. These factors contribute to the risk of infertility:
– Diabetes
– Poor nutrition
– Smoking (lowers sperm count and reduces erections)
– Hot baths
– Being very overweight or underweight
The environment may also affect fertility. Sperm counts are going down in industrialized countries due to unknown environmental factors.

Types of male infertility include:
1.) Azoospermia – This is a condition in which the man has no sperm in the ejaculate.
2.) Oligospermia – A condition in which there are low concentrations of sperm in the ejaculated fluid (semen).
3.) Asthenospermia – A condition in which the sperm are present but can’t swim normally.
4.) Teratospermia – A condition of high proportion of abnormally-shaped sperm.
5.) Retrograde ejaculation – A condition in which the tube through which sperm normally travels is blocked, causing sperm to retain in the man’s bladder.