It is not clear whether aging itself or the disorders associated with aging cause the gradual changes that occur in men's sexual functioning. The frequency, duration, and rigidity of erections gradually decline throughout adulthood. Levels of the male sex hormone (testosterone) tend to decrease, reducing sex drive (libido). Blood flow to the penis decreases. Other changes include decreases in penile sensitivity and ejaculatory volume, reduced forewarning of ejaculation, orgasm without ejaculation, more rapid detumescence, and a longer refractory period.
Breast Disorders in Men
Breast disorders, which include breast enlargement and breast cancer, occur infrequently in men.
• Breast Enlargement
Breast enlargement in males (gynecomastia) sometimes occurs during puberty. The enlargement is usually normal and transient, lasting a few months to a few years. Breast enlargement also commonly takes place after age 50.
Male breast enlargement may be caused by certain disorders (particularly liver disorders), certain drug therapies (including the use of female sex hormones and anabolic steroids), or heavy use of marijuana, beer, or heroin. Less commonly, male breast enlargement results from a hormonal imbalance, which can be caused by rare estrogen-producing tumors in the testes or adrenal glands.
One or both breasts may become enlarged. An enlarged breast may be tender. If tenderness is present, cancer is probably not the cause. Breast pain in men, as in women, is not usually a sign of cancer.
Generally, no specific treatment is needed. Breast enlargement often disappears on its own or after its cause is identified and treated. Surgical removal of excess breast tissue is effective but rarely necessary. Liposuction, a surgical technique that removes tissue through a suction tube inserted through a small incision, is the preferred surgical option and sometimes is followed by additional cosmetic surgery.
• Breast Cancer
Men can develop breast cancer, although 99% of all breast cancers develop in women. Because male breast cancer is uncommon, it may not be suspected as a cause of symptoms. As a result, male breast cancer often progresses to an advanced stage before it is diagnosed. The prognosis is the same as that for a woman whose cancer is at the same stage.
Treatment options are generally the same as those used for women (surgery, radiation therapy, and chemotherapy), except that breast-conserving surgery is rarely used. Estrogen makes some breast cancers grow. Estrogen is the main female sex hormone, but it is present in males in low amounts. If an examination of tissue samples shows that estrogen is making the cancer grow, estrogen is suppressed with drugs such as tamoxifen.
Resource: Merck Manual Home Edition