Problems with male fertility can be caused by a number of health issues and medical treatments. Some of these include:

  • A varicocele is a swelling of the veins that drain the testicle. It’s a common cause of male infertility. This may prevent normal cooling of the testicle, leading to reduced sperm count and fewer moving sperm.
  • Some infections can interfere with sperm production or sperm health, or can cause scarring that blocks the passage of sperm. These include some sexually transmitted infections, including chlamydia and gonorrhea; inflammation of the prostate (prostatitis); and inflamed testicles due to mumps (mumps orchitis).
  • Ejaculation issues. Retrograde ejaculation occurs when semen enters the bladder during orgasm instead of emerging out from the tip of the penis. Various health conditions can cause retrograde ejaculation, including diabetes, spinal injuries, medications, and surgery of the bladder, prostate or urethra. Some men with spinal cord injuries or certain diseases can’t ejaculate semen, even though they still produce sperm.
  • Antibodies that attack sperm.Anti-sperm antibodies are immune system cells that mistakenly identify sperm as harmful invaders and attempt to eliminate them.
  • Cancers and nonmalignant tumors can affect the male reproductive organs directly or can affect the glands that release hormones related to reproduction, such as the pituitary gland. In some cases, surgery, radiation or chemotherapy to treat tumors can affect male fertility.
  • Undescended testicles.In some males, during fetal development one or both testicles fail to descend from the abdomen into the sac that normally contains the testicles (scrotum). Decreased fertility is more likely in men who have had this condition.
  • Hormone imbalances.Infertility can result from disorders of the testicles themselves or an abnormality affecting other hormonal systems including the hypothalamus, pituitary, thyroid and adrenal glands. Low testosterone (male hypogonadism) and other hormonal problems have a number of possible underlying causes.
  • Sperm duct defects.The tubes that carry sperm (sperm ducts) can be damaged by illness or injury. Some men experience blockage in the part of the testicle that stores sperm (epididymis) or a blockage of one or both of the tubes that carry sperm out of the testicles. Men with cystic fibrosis and some other inherited conditions may be born without sperm ducts altogether.
  • Chromosome defects.Inherited disorders such as Klinefelter’s syndrome — in which a male is born with two X chromosomes and one Y chromosome (instead of one X and one Y) — cause abnormal development of the male reproductive organs. Other genetic syndromes associated with infertility include cystic fibrosis, Kallmann’s syndrome, Young’s syndrome and Kartagener syndrome.
  • Problems with sexual intercourse.These can include trouble keeping or maintaining an erection sufficient for sex (erectile dysfunction), premature ejaculation, painful intercourse, anatomical abnormalities such as having a urethral opening beneath the penis (hypospadias), or psychological or relationship problems that interfere with sex.
  • Celiac disease.A digestive disorder caused by sensitivity to gluten, celiac disease can cause male infertility. Fertility may improve after adopting a gluten-free diet.
  • Certain medications.Testosterone replacement therapy, long-term anabolic steroid use, cancer medications (chemotherapy), certain antifungal medications, some ulcer drugs and certain other medications can impair sperm production and decrease male fertility.