One question that crops up over and over again is whether having a vasectomy (the procedure that stops a man from making a woman pregnant) can lead to a later diagnosis of prostate cancer.
First of all, it has to be said that men who have vasectomies do appear to be more likely to have a diagnosis of prostate cancer 20 years later than men who do not have vasectomies. However, it also has to be said that there is absolutely no evidence whatsoever of a cause and effect relationship. In fact, there is good reason to believe that this is a statistical coincidence that has to do with the attitudes to health of the men most likely to have vasectomies.
Basically, men who have vasectomies exhibit what is widely described as “health-seeking” behavior. In other words, they are the type of men who look after their health, tend to go for regular check-ups, and generally have a lifestyle which could be considered as “healthy.” They are presumed to be more likely to have vasectomies because they have considered that the risks associated with a vasectomy are far lower than the risks associated with their wife/partner having a late or unwanted pregnancy. (Of course there is also the outside possibility that they see the doctor more often and they have vasectomies because their wife or partner talks them into these things!)
Now it is also reasonable to suppose that men who exhibit health-seeking behavior are more likely to seek regular prostate examinations as part of that behavior. This immediately implies that the same men who seek vasectomies are more likely to have a prostate examination than the men who do not have vasectomies. Therefore these men are more likely to be diagnosed with prostate cancer!
The bottom line is that men who have vasectomies are somewhere between 1.5 and 2.0 times more likely to have a later diagnosis of prostate cancer than men who have not had a vasectomy … but we have no reason to believe that there is any connection between the two.