What are the main causes of male sterility and infertility?

What are the main causes of male sterility and infertility?

The male partner’s role in infertility has, historically, been undervalued and underdiagnosed for cultural and social reasons. However, we are now seeing progress in the analysis of men and a growing interest amongst patients in their fertility issue. Consultations for men with difficulties having children are increasingly common.

The causes of male sterility (male factor) have seen a significant increase over the last few years and are now responsible for up to 50% of cases of sterility in couples. Up to 30% of cases of infertility are due to the male factor alone and in a further 20% of cases there is a combination of both male and female factors. This is why urological examination of the male partner is so important during the couple’s fertility analysis.

Many situations can lead to male infertility. They are, in most cases, connected to abnormalities in semen (sperm count and sperm quality issues, or both). For example, oligozoospermia (low concentration of spermatozoa and poor mobility), azoospermia (an absence of spermatozoa in semen). This may be because they become obstructed on exiting the ejaculatory ducts or vas deferens – obstructive azoospermia – or due to problems in spermatozoa production – non-obstructive azoospermia.

Abnormalities in ejaculation such as retrograde ejaculation (sperm redirected to the urinary bladder), premature ejaculation (expulsion of semen only a few seconds after penetration) or anejaculation (an absence of sperm which is common in patients with spinal cord injuries) are also causes of male infertility.

Hormonal issues such as hypogonadism (diminished levels of testosterone) due to testicular failure or due to failure of the central core in charge of production, mean that spermatozoa do not develop normally and, therefore, fertility is jeopardised.

Environmental factors such as exposure to gonadal toxins, tobacco, alcohol, etc. also predispose the body to the male factor. The patient’s age is a factor that should be taken into account since sperm quality decreases with age (particularly in terms of damage to sperm DNA).

Another reason for fertility issues are urological abnormalities such as hypospadias (the urinary opening is incorrectly positioned, generally in the rear part of the urethra) that mean semen is not correctly delivered to the vagina; phimosis, which sometimes renders sexual intercourse and, therefore, fertility problematic; tumour-based issues such as tumours in the testicles can mean that men undergoing medical treatment or radiotherapy to treat this condition find that their ability to conceive is jeopardised and they turn to us. In the case of cancer patients, it is essential that semen samples are taken (stored semen or frozen semen) before undergoing healthcare treatment so that patients can be offered different options for having children of their own once they have completed treatment.

Around 70% of the causes of infertility in men can be diagnosed during a consultation with an urologist specialising in reproduction, accompanied by an in-depth physical examination, a semen analysis (seminogram), a hormone analysis and, should it be necessary, a scrotal ultrasound. Correct diagnosis of such conditions means that treatment can be carried out and this generally leads to the couple’s objective being accomplished: pregnancy. This is why, at Instituto Bernabeu, we point out the importance of a proper study of the male partner as a part of the couple’s fertility analysis.


  • Male infertility: an overview of causes and treatment options. Rachel Busuttil Leaver. British Journal of Nursing, 2016, (Urology Supplement) Vol 25, No 18. S35-S40.
  • Limitations and barriers in access to care for male factor infertility. Akanksha Mehta, M.D. et al. Fertility and Sterility. Vol. 105, No. 5, May 2016. 1128-1137.

Let's talk

We can help you with a no-obligation