There appears to be little relationship between ejaculation and the risk of prostate cancer in men, except perhaps at the highest rates of ejaculation where there appears to be a slightly protective effect. The research appeared in the April 7 edition of JAMA, the Journal of the American Medical Association.
The researchers, led by Michael F. Leitzmann at the National Cancer Institute, surveyed nearly 30,000 health professionals aged 46 to 81, every two years between 1992 and 2000. They defined ejaculation as including sexual intercourse, nocturnal emission, and masturbation.
Leitzmann speculated that perhaps more frequent ejaculations, more than 21 times a month, may reduce concentrations of compounds and the formation of crystals that are associated with prostate cancer.
Research from India, published in the March 27 issue of The Lancet, adds further support to the notion that being circumcised helps protect heterosexual men from becoming infected with HIV.