Varicose veins of the testicle
Childhood conditions
Genetic cause of poor sperm production
Genetic cause of blockage of sperm
Hormonal imbalance
Improper timing of intercourse/difficulty with intercourse
Cancer
Spinal cord injury/Abnormal ejaculation
Blockage of the ejaculatory ducts
Infection/inflammation
Toxic/occupational exposure
Heat exposure /Fevers
Illness/Medications
Substance abuse
Age
Vasectomy