Recent studies are showing that estrogen exposure, typically through the water system, may increase the risk of prostate cancer in men. It's been proven that excess estrogen can cause various cancers; the fact that widespread, increased use of contraceptive pills over the past 40 years might have impact on environmental levels gave reason for researchers to further investigate.
The research went on to see whether or not there was an association between women's use of oral contraceptives and the rate of prostate cancer or death. Minimal amounts of estrogen are excreted by a woman normally, but when it occurs from millions of women over a long period of time, there may be low-level environmental pollution.
Out of the 100 countries researchers examined, those countries that had high usage of oral contraceptives also had high incidences of prostate cancer. To solidify the correlation between the two, research teams are planning to test water samples and investigate the estrogen levels in patients with prostate cancer.
It's important to note that prostate cancer is the most frequent cancer in males within the developed world.