- Sperm Development
- Incidence and Prevalence
- Causes and Risk Factors
- Retrograde Ejaculation
- Testicular Trauma
In men, hormone disorders, illness, reproductive anatomy trauma and obstruction, and sexual dysfunction can temporarily or permanently affect sperm and prevent conception.
Some disorders become more difficult to treat the longer they persist without treatment.
Cell division produces mature sperm cells (spermatozoa) that contain one-half of a man’s genetic code. Each spermatogenesis cycle consists of six stages and takes about 16 days to complete. Approximately five cycles, or 2 ½ months, are needed to produce one mature sperm. Energy-generating organelles (mitochondria) inside each sperm power its tail (flagellum) so that it can swim to the female egg once inside the vagina.
Sperm development is ultimately controlled by the endocrine (hormonal) system that comprises the hypothalamic-pituitary-gonadal axis. Because sperm development takes over 2 months, illness that was present during the first cycle may affect mature sperm, regardless of a man’s health at the time of examination.
Infertility can result from a condition that is present at birth (congenital) or that develops later (acquired).
Causes of infertility include the following:
- Defect or obstruction in the reproductive system such as failure of testes to descend into the scrotum (cryptorchidism) or absence of one or both testicles (anorchism)
- Disease (e.g., cystic fibrosis, sickle cell anemia, sexually transmitted diseases [STDs])
- Hormone dysfunction (testosterone deficiency; caused by a disorder in the hypothalamic-pituitary-gonadal axis)
- Infection (e.g., prostatitis, epididymitis, orchitis; can cause irreversible infertility if they occur before puberty)
- Injury (e.g., testicular trauma)
- Medications to treat high blood pressure (hypertension) and digestive disease
- Metabolic disorders such as hemochromatosis (affects how the body uses and stores iron)
- Systemic disease (high fever, infection, kidney disease)
- Testicular cancer