Can masturbation really cause cancer?

"Researchers surveyed 800 men, about half of whom had suffered prostate cancer, and found that the more sexual activity they had engaged in as young adults, the more likely they were to have been stricken with the disease. A higher rate of intercourse did contribute to this discrepancy, but most of the difference was attributed to self-love."

My husband commented that most of the researchers must have been women.
No comment to the comment.