A normal prostate is a gland about the size of a walnut. Composed of two lobes with an outer layer of tissue, it sits just below the bladder and surrounds the urethra, the tube which carries both urine and semen down to the opening of the penis. The prostate carries out several important functions. It produces some of the fluid that makes up semen, including an alkaline liquid that protects sperm from any acidity in the vagina; it helps pump the semen out during ejaculation; and it seals off the bladder during climax, so that urine doesn't mix with the sperm.

It's strictly a male issue, as women don't have a prostate or anything comparable. And it's also a male problem in that, as you age, you can probably expect to have some concerns about it. The most common problem with the prostate is benign prostatic hyperplasia, also called benign prostatic hypertrophy, or simply BPH. This is when the prostate enlarges - for reasons not entirely known - creating pressure on the urethra and, in advanced cases, the bladder. The prostate can also be subject to prostatitis, an inflammation of the gland, and to cancer.

While prostatitis is the most common prostate problem in men under the age of 50, the possibility of BPH begins when a man is around 30: approximately eight percent of men between the ages of 30 and 40 have the condition. It becomes more likely with age, with some 80 percent of octogenarians affected by the condition. Men in their 90s almost inevitably have some degree of prostate enlargement.

Because the prostate surrounds the urethra, any enlargement will put pressure on that tube. Problems with urination are the most common symptoms of BPH, including a frequent, urgent need to urinate, which may wake you up at night; difficulty starting to urinate, even though it feels urgent; a weak urine stream or a small amount of urine; the feeling of still having to go even after you've finished; dribbling after urination; or blood in the urine.

For most men, the symptoms are irritating but not life-threatening: although men can have BPH and cancer at the same time, having BPH doesn't mean you have or necessarily will develop prostate cancer. BPH becomes serious when the gland blocks the flow of urine altogether, which can require catheterization and possibly surgery. Be careful about over-the-counter cold and allergy drugs if you have BPH, as some antihistamines and decongestants can bring on a condition where urine can't escape.

Comedians get a lot of mileage out of the sound of a rubber glove snapping, but a rectal exam is the best way for your doctor to monitor prostate size. The causes of BPH aren't entirely known, but most doctors will tell you that a healthy lifestyle is always good preventative medicine. Limiting caffeine and alcohol, watching your weight, exercising regularly, quitting smoking, eating fresh fruits and vegetables, and avoiding fatty foods will go a long way. Many men take saw palmetto, a herbal supplement long used in Europe and now in the United States to help control BPH. And here's one you'll love: research shows that men who ejaculate frequently tend to have healthier prostates. Now there's a prescription you'll want to fill.