Does having a vasectomy make you more prone to prostate cancer? The research went back and forth for years – six studies published before 2014 were evenly divided divided between yeas and nays – but now new research purports to deliver the final and definitive word.

“Although a previous study suggested an association, our results show no connection between vasectomies and overall risk for prostate cancer, or of dying of prostate cancer, and should provide some reassurance to men considering vasectomy,” Eric J. Jacobs, PhD, cancer epidemiologist at the American Cancer Society, said. “Men concerned about developing a fatal prostate cancer should focus on maintaining a healthy weight and, if they smoke, quitting smoking. Both obesity and smoking having consistently been linked with high risk for fatal prostate cancer, as well as with risk for many other diseases.”

Jacobs and his team looked at data from 363,726 men in the Cancer Prevention Study II (CPS-II) cohort, and data from 66,542 men from the CPS-II Nutrition Cohort. In total, 42,015 men in the CPS-II cohort and 10,589 men in the CPS-II Nutrition cohort had a vasectomy. In both data samplings, men with vasectomies were less likely to be obese or current smokers and were more likely to have more education.

More interesting still, having a vasectomy was associated with a lower risk for prostate cancer mortality in the CPS-II Nutrition cohort. The researchers noted they were surprised by that data.

“Because this study, like all observational studies, has some potential for bias, a small increase in risk cannot be entirely ruled out,” Jacobs and colleagues wrote. “However, our results provide some reassurance that vasectomy is unlikely to meaningfully increase risk for prostate cancer.”