Infertile men may be more prone to developing high-grade, aggressive prostate cancer that grows and spreads quickly, a study has revealed.
Medical experts used 22,000 men assessed for infertility at 15 Californian clinics in the US as a study group.
A total of 4,500 men were confirmed as being infertile and these were 2.6 times more likely to be diagnosed with high grade prostate cancer than 17,500 men who were tested and found not to be infertile.
Scientists think there may be as-yet unknown common biological pathways underlying both infertility and prostate cancer.
The incidence of prostate cancer in the whole study group was compared with that of a sample of men of similar age from the general population. A total of 168 cases of the disease developed among the study group - slightly less than the expected rate of 185.
The findings were reported in the journal Cancer.
The team led by Dr Thomas Walsh, from the University of Washington in Seattle, said if the results were confirmed by other studies it may be appropriate for infertile men to be considered for early prostate cancer screening.
But Dr Helen Rippon, head of research management at The Prostate Cancer Charity, pointed out the number of men in the study diagnosed with aggressive forms of prostate cancer was very small, making it difficult to interpret the results.