In about half of infertile couples the problem lies either solely with the male or in both the male and female partners.
However, the cause of infertility in the male partner is often difficult to determine and many men are diagnosed with ‘idiopathic male infertility’.
A recent study published in Human Reproduction, reported that only 40% of men with severe male infertility could be assigned a definite cause and these were mostly for the most severe cases. Although varicocele and leukocytpspermia were more common amongst infertile men than fertile control men, these conditions were not deemed to be the primary causes of infertility in these men.
The authors concluded that there is a need for more research to understand the causes and mechanisms of the less severe cases of male infertility.