Vasectomy remains one of the most effective means of birth control, with an average reliability of 99%. Some men, though, balk at undergoing the procedure in light of studies that have suggested an increased risk of prostate cancer in men who have undergone vasectomy. However, there is no plausible reason why vasectomy, which involves tying and cutting the tubes that carry sperm, would increase prostate cancer risk. Men who undergo vasectomy tend to be health-conscious individuals who see their physicians frequently. As such, their higher prostate-cancer rates, found by some studies, may just be a reflection of better diagnosis. A recent review by the National Institutes of Health concluded that the overall evidence suggests no association between vasectomy and cancer.