The most common cause of male infertility is the defect in sperm production (spermatogenesis), leading to semen analysis or seminograms with low sperm count or low mobility. This is the problem in 65-80% of men who have difficulty getting pregnant.
This is due to a failure at the testicular level, and in the vast majority of cases we are not able to find a cause for it. In a smaller percentage of cases we can explain this failure by:
- Genetic alterations, such as Y chromosome microdeletions or Klinefelter syndrome.
- Cryptorchidism: damage to spermatogenesis in patients with a history of lack of testicular descent is related to genetic and hormonal causes, which may be partially reversible with early surgical intervention to lower the testes.
- Alterations in the hormonal receptors of testosterone, estrogens or FSH.
- Diseases such as myotonic dystrophy.
- Varicocele, although in the vast majority of cases these patients will present normal seminograms (normozoospermia)
- Testicular infections due to mumps, STDs such as chlamydia, gonococcus or HIV.
- Chemotherapy or radiation therapy
- Environmental pollution
Other less common causes of male infertility would be:
- Idiopathic male infertility: men who, despite having normal seminograms, do not achieve pregnancy (10-20%).
- Obstructive azoospermia (5%): In these patients, sperm production at the testicular level is normal, but the ducts that must allow these sperm to escape into the ejaculate are not permeable. This can occur due to infections, genetic alterations (such as cystic fibrosis), etc.
- Endocrine disorders (2-5%): a failure at the brain level can produce hypogonadism, so that the testicle does not receive the proper orders to carry out correct spermatogenesis. This can be due to congenital alterations, tumor processes, drug use such as opioids or cannabis, obesity or serious systemic diseases.