In about 1/3 of couples who have problems getting pregnant, the cause lies with the man. Most often, this concerns reduced sperm production or sperm quality, which may be due to hereditary conditions and diseases, but environment and lifestyle are also contributory factors.
Reduced sperm quality
Reduced sperm quality may be triggered by diseases, but it may also be congenital. The following may be fertility-reducing factors:
- Mumps in childhood
- Undescended testicles (the testicles have not descended into the scrotum).
- Varicocele
- Failure in production of sex hormones
- Genetic causes (chromosomal disorders)
- Environmental impacts