Although, the diagnosis of prostate cancer is devastating, the disease is highly treatable. Treatment, however, does have side effects that can drastically affect sexual function-both from a physiologic and psychological standpoint. This problem can be particularly difficult for gay men to deal with as many are too afraid or embarrassed to discuss altered sexual function with their physicians and sexual partners. Physicians may incorrectly assume that an unmarried male patient is not sexually active when he may, in fact, be very sexually active. Sexual dysfunction after prostate cancer treatment can include impotence or a weak erection, failure to ejaculate and anal discomfort. Radiation therapy may produce impotence that is of gradual onset often beginning after treatment has terminated. Surgery can produce impotence immediately after the operation that can gradually improve over time. External beam radiation can also affect a gay man's ability to have anal sex because of bleeding, diarrhea and discomfort. Younger men, men with less extensive prostate cancer and those who have had an active sex life before developing prostate cancer are less likely to experience difficulties with sexual function after cancer treatment. This article discusses treatment options for sexual dysfunction including medication, sexual aids, and surgery to restore erections. Communication between sexual partners and physicians is also crucial for dealing with alterations of sexual function. Sex with another man did not cause the prostate cancer and it will not cause it to return. KEYWORDS. Anal sex, cancer, ejaculation, erection, gay, homosexuality, impotence, leuprolide, masturbation, potency, proctitis, prostate gland, prostatectomy, radiation therapy, semen, sex, sexual function, sildenafil, tadalafil, vardenafil