Teratozoospermia is the abnormal sperm morphology, caused by defects in the head, midpiece, and/or tail. According to the criteria published in 2010 by the World Health Organization (WHO), a man has teratozoospermia when more than 96% of the sperm he produces are abnormally shaped.

Teratozoospermia is associated with male infertility in all cases, as it means that sperm are unable to get to the egg due to their abnormal shape.

The causes of abnormal sperm morphology are varied and, in most cases, difficult to determine.

The following are the most common ones:

  • Genetic traits
  • Cancer treatments (chemotherapy and radiotherapy)
  • Bacterial infections in sperm and orchitis
  • Testicular trauma
  • Testicular disorders, like varicocele
  • Fever
  • Diabetes mellitus (DM) or meningitis
  • Tobacco, alcohol, and street drug use
  • Unhealthy habits: unbalanced diet, exposure to toxic substances, too tight clothes, etc.