At least, according to the July Playboy Advisor, it does.
Q. Does regular masturbation reduce the chance that you'll get prostate cancer?
A. Apparently yes. You'll go blind and grow hair on your palms, but you'll live forever. Scientists at the National Cancer Institute examined, over eight years, the self-reported ejaculation frquency of nearly 30,000 men. Those who came most often -- a lifetime average of 21 times a month -- were one-third less likely to develop organ-confined or slow-growing prostate cancer than the control group of men, who came four to seven times a month. The study found a benefit in men who had more than 12 orgasms a month. Regular ejaculation may be beneficial because it flushes out carcinogens in the gland. Come for life. And get an exam annually after you hit 50. If you're African-American or have a family history of prostate cancer, start at 40.
This has been a Public Service Announcement. Gentlemen, start your engines!