Fertility:

In about 40% of infertile couples, the cause of the infertility lies with the males. There are many reasons for male infertility. 

Quick Fact: It takes approximately 72-90 days to produce mature sperm. Sperm is produced 24 hours a day, 7 days a week. 

There are many factors that can decrease or cease sperm production. Here are a few:

Illness

Excessive Caffeine

Stress

Street and certain Prescription Drugs

Some over the counter medications

Injury to the testicles

Blockage in the Vas Deferens

Varicocele

Excessive Heat

Vitamin Deficiencies
 

Impotency:

Impotence is the inability of a man either to have an erection or to keep the penis erect long enough to have sexual intercourse. This is a common problem affecting as many as 10 million men in the United States. By the time most men are 40 they have already experienced impotence at some time in their lives.

When just a single incident occurs, the best thing to do is forget about it. Problems arise when this difficulty starts occurring regularly.

According to an article published in early 1993 (review: Morley, 1993), approximately 10 million men in the U.S. have problems with impotence.

Men afflicted with repeated impotence tend to be middle-aged and older, with such a condition most common in men 60 years of age and older. Regardless of the age, however, many men who have this problem can be treated successfully.

Impotence can result from a wide variety of problems. As with any other ailment, when a person begins having this problem repeatedly, he needs to see a doctor. The doctor will want to rule out the possibility of disease, injury, or side effects from medicine.

For example, cardiovascular problems, diabetes, injuries to the spinal column, and side effects from high blood pressure medicine are among the physical conditions that can lead to impotence. An erection occurs when the nervous system activates a rapid increase in blood flow. The vascular muscle in the spongy area becomes engorged with blood and outflow of blood is cutoff. Erection can be elicited by the so-called reflex erection as we see in spinal cord patients, or can be caused by psychogenic stimulation. Numerous sexual stimuli are processed by the brain and transmitted to the penis via the nervous system. In order to get an erection, the blood flow must increase and, at the same time,  the blood has to be prevented from leaving the penis.