Male infertility: causes of sterility
Dysfunctional sperm maturation
The most common problem with fertility in men is insufficient production of normal, motile sperm in the testes. Semen quality is considered normal when the number of sperm cells is over 20 million per millilitre of semen. Of these, at least 15 percent should be normally formed and 25 percent should have good forward mobility. If these values are not achieved, the man’s fertility is reduced. However, even if the sperm count is normal, a functional problem could still prevent the sperm from penetrating the egg.
Dysfunction in sperm maturation can result from a mumps infection in childhood. Varicose veins on the testes (varicocele) can also cause poor sperm motility.
Other causes are hormonal problems, stress, environmental pollution, undescended testicles, tumours that have been operated on or genetic causes, such as chromosomal abnormality. Acute infections can also temporarily reduce sperm motility.
Concrete causes for male infertility can occasionally be treated but, in fact, men can actively improve their own sperm quality.
Dysfunctional sperm transport
In four per cent of cases, sufficient sperm is actually formed – but these fail to penetrate the woman’s body during ejaculation because the seminal ducts are blocked.
This situation is comparable to a blocked fallopian tube in the woman. It could be caused by prior sterilisation, undeveloped epididymis or adhesions in the epididymis. Adhesions in the epididymis may result from infections.