The patients couldn’t always understand why, if they came complaining of thrush, a painful penile discharge or impotence, they should have their blood pressure measured, their heart listened to, their carotid arteries in the neck assessed and their urine tested not only for pus but also for sugar.

Despite some earlier professional ridicule, Dr Dunlop was proved right about the major significance of chlamydial infections; he is now being shown to be wise about the importance of genital symptoms in the diagnosis of problems in other parts of the body.

Many doctors have been reluctant to discuss potency when a man complains of chest pains or breathlessness on exercise, and equally reluctant to get out the stethoscope and the sphygmomanometer to take the patient’s blood pressure when he admits to having troubles with erections. Even a moment’s thought would prompt the idea that if a patient’s coronary arteries are becoming so narrowed that the heart is starved of blood to the point at which they suffer angina, so may the pelvic arteries that lead to the penis be furred up — and that organ may have a blood supply no longer adequate to provide the pressure necessary for an erection.

Remembering Dr Dunlop’s dictates, my former patients for many years have been subjected to a full medical examination, including blood and urine tests and an exercise ECG, if they complained of erectile dysfunction. A report of research from the University of Texas Health Centre, published in the Journal of the American Medical Association (JAMA), vindicates the Dunlop approach to genito-urinary medicine. It has shown that erectile dysfunction is as strong a predictor of future or existing heart disease as smoking or family history. From my own experience early middle-aged men who complain that their erections are no longer what they were need to have cardiovascular assessments.

Dr Ian Thompson, the lead author of the JAMA report and chairman of the department of urology at Texas University, compared for seven years the general health of 3,816 men who admitted to erectile dysfunction with 4,247 men with normal sexual function. Men who had reported problems with potency either before the study started, or during the seven years it ran, had a 45 per cent increased risk of a cardiovascular event compared with those who had no troubles with their erections.

Difficulties with erections remained an important warning sign of a potential cardiovascular problem even after allowance had been made for smoking, abnormal cholesterol levels, family history of heart disease or a present or past history of smoking.

The study showed that impotence was linked with a wide range of cardiovascular problems: men with erectile dysfunction were more likely to suffer angina, coronary heart attacks, cardiac arrhythmias, strokes and other heart problems. No steps were taken to evaluate the effect that drugs taken to alleviate cardiovascular problems might have on the data collected at Texas University.

This new research emphasises how important it is that during the examination of a patient with cardiovascular symptoms, when talking about possible complications, the doctor also discusses the possibility of impotence, lest the patient is too shy to mention it spontaneously.

Likewise, no patient should be prescribed treatment for impotence without the possibility of cardiovascular disease and diabetes being considered and excluded. The earlier heart disease and diabetes are treated the better the long-term outlook. The treatment for both conditions has improved dramatically in the past 15 years. Even more remarkable is the difference that the advent of Viagra, Cialis and Levitra have made to both the understanding and treatment of impotence.