IT'S a subject most men avoid talking about, yet its implications for a relationship are just as tragic as alcoholic, physical or verbal abuse of one partner against another.
Erectile dysfunction is a medical condition that has affected men since the beginning of humankind - but it's only in recent times that medication has become available for what is a very common condition.
Well Mens Clinic International, a medical organisation that specialises in male sexual dysfunction, has 60 branches throughout South Africa, with its Sandton outlet catering for more than 30000 patients.
According to Nick Colley, a doctor who works for the group, there are three basic problems that can affect a man's sexual performance.
"The first is either a weak erection or the inability to maintain one. Next is premature ejaculation, where a man ejaculates before satisfying a women. Thirdly is low libido, where a man has a low desire to have intercourse," he explains.
Causes for the problem are wide and varied ... from poor lifestyle (drinking and smoking too much) to organic causes such as high blood pressure, diabetes, cholesterol to emotional and psychological problems.
It is a condition that can affect men of any age.
"The oldest patient I've had was 93 years old," Colley says. "I also had a man of 91 who was in a wheelchair and had only one leg and one eye. He was looking for a solution to his problem."
After digesting that I can't help but say: "You must be joking!"
He assures me he isn't. I told him I admire him for being so ambitious. At least he was a trier.
But the condition affects all age groups.
"We get men in their 20s coming for help but the problem normally starts for men in their forties."
Having just celebrated a 40-something birthday last week, I fidget nervously in the chair opposite his desk.
The good news, though, is that 90 to 95 percent of cases can be cured if patients take the medication prescribed on a regular basis.
Treatment begins with a medical at which a man's sexual habits are discussed and then a full medical is conducted.
An erection-function test is t conducted in which an injection is administered directly into the penis. Within 20 to 40 minutes an erection is obtained, which is tested for strength so that the right doses of medicine can be administered.
Sounds painful but Colley says there is nothing to worry about.
" It is totally painless and is similar to a diabetic administering an insulin injection. You use a small syringe. There are no side effects and is totally safe," he says.
Once the amount of medicine is decided on the patient administers the injection to the penis twice a week, 20 minutes before intercourse.
Treatment will normally carry on for between three and six months and during that time a helpline is available to assist patients with any queries and advice they might require.
Colley advises against using the multitudes of so-called "doctors" who advertise in the classified sections of many newspapers .
"In their own minds they (the advertisers) probably believe their products will work. The public use them because they are an easy and quick fix. You don't have to make an appointment. It's a question of getting your product over the counter and you're on your way."
He warns those who are tempted to use penis enlarging creams.
"Overall they are not really successful. At Mens Clinic, if we feel a patient has a particularly small penis, we will refer him to a plastic surgeon or urologist."
Is there any embarrassment for black men to be talking to a white doctor on such a sensitive subject?
"Not at all. Many black people are used to consulting a white doctor. That said, a high percentage of doctors working for the group are African."
Fortunately many medical aids cover costs because they view the problem as a medical condition.
Hailed as one of medicines greatest discoveries, Colley is wary of the wonder drug Viagra.
"It is a brilliant modern medication in assisting to get an erection. But there are side effects.
"It must be used with extreme caution and is not something to be used casually. If used selectively it has its place."
Before joining Mens Clinic, Colley was a general practitioner for 30 years when he decided to take things easier.
After completing a course in sexology he imagined himself working three mornings a week in a less stressful environment.
"It started off as three mornings but has somehow turned into six days a week," he says. "What we are doing is revolutionising relationships from a sexual point of view.
"Many couples are unhappy because the man is unable to deliver and the woman begins to believe that she is not attractive anymore."
On the back of Colley's business card is a warning: "Do not let your erection remain for longer than four hours without contacting the emergency numbers on the front of the card."
I can't help thinking it's a pity the 91-year-old with one leg and one eye never got the chance to use that emergency number!