Many perceive infertility as a condition that only affects women, but about 9% of men* have issues that interfere with their ability to achieve a pregnancy.

Pre-testicular Infertility

Pre-testicular infertility is typically associated with hormone production. Often, problems originate in the pituitary gland, a pea-sized structure in the brain that releases hormones into the bloodstream. If the pituitary gland is underproductive in a male, then the gonads (testicles) may not receive luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which are essential for reproduction.

Infertility may also be the result of prolactinoma, a condition in which a benign growth within the pituitary gland overproduces the hormone prolactin, which decreases production of the hormone testosterone, and hinders male reproductive abilities.

Finally, taking supplemental testosterone can shut down the pituitary gland's production of reproductive hormones.

"When the brain sees high levels of testosterone in a man's system, the pituitary gland will decrease production of LH and FSH, so testicles won't get the signal to make testosterone or sperm. Since testosterone production in the testicle itself is very important for sperm production, this can cause infertility," says Dr. Brannigan. "Taking testosterone may cause temporary, and in some cases permanent, infertility."

A hormonal intervention to balance male reproductive hormones and optimize sperm production is often the first line of treatment for pre-testicular infertility caused by hormones.

Whether due to anatomy or a genetic disorder, some people have testicles that do not make sperm.

People who have Klinefelter syndrome are born with an extra X chromosome, which commonly results in smaller testicles that have very limited sperm production. They typically experience infertility, but reproductive urologists have success in isolating sperm from these patients over 50% of the time. These sperm can be used in special laboratory procedures called assisted reproductive techniques to help achieve a pregnancy.

Some individuals are also born with undescended testicles, which can cause infertility.

Azoospermia is another cause of infertility. This is a condition where the semen contains no sperm at all. Those with azoospermia will often have a small number of sperm cells in the testicles, but these sperm are so few and far between that they do not make it into the semen. In this case, a surgical procedure can be performed to extract the healthiest sperm cells from the testicles to use for in-vitro fertilization (IVF). According to Dr. Brannigan, the success rate for this procedure is about 50%.

Post-testicular Infertility

Typically, post-testicular infertility is caused by an obstruction in the pathway of the sperm. This can be due to a prior vasectomy, a genetic condition or an underlying illness. An infection can inflame the tissue of the epididymis or vas deferens, the tubes that store and carry sperm from the testicles to the urethra, causing temporary infertility. People assigned male at birth with cystic fibrosis (CF) or who carry the gene for CF are often born without a vas deferens, which means their sperm can't exit the testicles. Sexual dysfunction is another form of post-testicular infertility. This includes conditions such as the inability to sustain an erection during sexual intercourse and also retrograde ejaculation, where the semen flushes back into the bladder instead of out of the urethra.

Another common cause of post-testicular infertility is a varicocele, or a dilation of the veins near the testicles within the scrotum and carry blood away from the testicles.

"A simple analogy for a varicocele is like varicose veins occurring around the testicle," says Dr. Brannigan. "There's blood pooling around the testicles, making them too warm to produce sperm, causing infertility."

About 15% of men* have varicoceles. This condition commonly develops during the teenage years.

Most post-testicular infertility issues can be corrected with minimally invasive surgery.

Learn more about infertility.