As sexual virility is associated with manliness, problems with erections understand­ably upset men. Erectile dysfunction (ED), also called impotence, is characterized by a man’s inability to have an erection hard enough to have sex or to keep an erection long enough to finish sexual intercourse.

However, one of the most important factors concern­ing a man’s erection is in the mind. Dr Damian Png, consultant urologist at Singapore’s MD Specialist Healthcare, said: “The brain is the biggest sex organ.

He explained that the brain processes all senses such as the tactile feel of skin or silk, the scent of perfume, melody of music and suggestive sen­sual visual stimuli.

These signals are then sent down the spinal cord and via nerves to the penis, which fills up with blood as a result of blood vessels opening up on stimulation. The penis gets rigid and becomes erect.

An erection thus requires the interaction of a man’s brain, nerves, hormones and blood vessels. Png said common causes of ED include problems related to blood vessels and nerves, such as diabetes, decreased male hormones due to aging and painful intercourse due to a crooked penis. He said that some medica­tion, such as antidepressants and those for blood pres­sure or prostate enlargement conditions, could also cause impotency problems.