Sexual dysfunction prevalence vary widely, but is much higher in the general population than most people are willing to accept.
Causes include: smoking sedentary lifestyle, poor general health, endocrine, cardiac, circulatory, structural, psychological, social, marital and other idiopathic causes. Because of this complexity it is difficult to make the correct diagnosis as to its cause, even when Propecia (finasteride) is not in the mix as shown in a recent survey of patients in a Canadian primary care setting where there was reported a 49.9% prevalence of erectile dysfunction in 3921 men 40-88 years of age (ave. = 56.7) and 30% prevalence in men in their 40’s. Although there is a statistically small relationship between finasteride and erectile dysfunction, the connection is far less significant than the reports in the general population (* see reference below).
Ref: Grover S, Lowensteyn I. The prevalence of erectile dysfunction in the primary care setting: Importance of risk factors for diabetes and vascular disease. Arch Intern Med 2006: 166; 213-219.