To quote from the book:
"Recent research has found that frequent and/or long-term marijuana use may significantly increasea man's risk of developing testicular cancer. The researchers found that being a marijuana smoker at the time of diagnosis was associated with a 70 percent increased risk of testicular cancer. The risk was particularly elevated (about twice that of those who never smoked marijuana) for those who used marijuana at least weekly or who had long-term exposure to the substance beginning in adolescence. The results also suggested that the association with marijuana use might be limited to nonseminoma, an aggresive, fast-growing testicular malignancy that tendsto strike early,between 20 and 35, and accounts for about 40 percent of all testicular cancer cases" (Donatelle 218).