The genesis of male infertility is to some extent unresolved. The most common problem is an impairment of spermatogenesis (sperm cell production), due to genetic or exogenous factors.
Generally, males produce about 20 million sperm cells per millilitre of seminal fluid. Lower sperm concentrations indicate impaired male fecundity.
Semen analysis is able to reveal the following deviations:
- Low sperm count (oligospermia)
- Absent sperm production (azoospermia), due to testicular malfunctions or obstruction of the transport route
- Insufficient sperm motility (asthenozoospermia); the consecutive inability of sperm cells to ‘swim’ through the cervix and meet the oocyte in one of the Fallopian tubes.
- Deviant sperm morphology (teratozoospermia), which makes sperm cells incapable of penetrating the oocyte’s outer layer.
List of possible causes of reduced sperm quality:
- Malfunctioning sperm production, due to:
- Inflammation (for example mumps)
- Testicular varicoses (varicocele)
- Hormonal imbalances
- Previous surgery, chemotherapy or radiation treatments
- Or often unclear, spontaneous reasons (idiopathic).
- Interruption of sperm transportation, due to:
- Hereditary congenital malformations
- Ejaculatory dysfunction (nerve paralysis; impotence)
- Obstruction or occlusion of efferent seminal transportation, due to congenital bilateral aplasia of the seminal duct; testicular torsion
- Inflammatory changes, such as epididymitis, prostatitis, urethritis
- Or male sterilisation (vasectomy).
- Genetic disorders
- Lebensweise (Stress, Nikotin, Fehlernährung, Anabolika, Umweltfaktoren)
Immunologic infertility can also be a likely cause of the inability to conceive, which is where the female body produces antibodies against male sperm.