clipped from: news.bbc.co.uk   
Men could reduce their risk of developing prostate cancer through regular masturbation, researchers suggest.

They say cancer-causing chemicals could build up in the prostate if men do not ejaculate regularly.

And they say sexual intercourse may not have the same protective effect because of the possibility of contracting a sexually transmitted infection, which could increase men's cancer risk.

Prostate scans
This is a plausible theory
Dr Chris Hiley, Prostate Cancer Charity
They found those who had ejaculated the most between the ages of 20 and 50 were the least likely to develop the cancer.
The protective effect was greatest while the men were in their 20s.
Men who ejaculated more than five times a week were a third less likely to develop prostate cancer later in life.
This is a plausible theory
Dr Chris Hiley, Prostate Cancer Charity