Scientists at Harvard University say men who have a vasectomy have a greater risk of developing the most aggressive form of prostate cancer.
The scientists analysed medical records from nearly 50-thousand men and found that those who had the operation were 10-percent more likely to be diagnosed with the disease.
The study revealed a stronger link with the most serious forms of prostate cancer, with rates of advanced or lethal disease rising by 20-percent in men who had the procedure.
The danger seemed to be highest among men who had a vasectomy before the age of 38.
Cancer charities said the study was extremely important and urged doctors to discuss cancer risk with men who were considering sterilisation.
