Male reproductive ageing: human fertility, androgens and hormone dependent disease

The waning of male virility with age, in all its ambiguities, has always intrigued humans, prompting innumerable approaches to staving it off. In modern terms, advancing age impacts on all aspects of male reproductive health sexuality, fertility and androgenization with differing extents and tempo. With ageing, male sexual function declines predominantly due to vasculogenic defects in cavernosal haemodynamics, whereas libido and ejaculation are less affected. This raises the potential for prevention and treatment of erectile dysfunction as an early clinical manifestation of atherosclerosis. After maturity, male fertility persists throughout life but decreases modestly with age presumably due to concomitant decline in sexual activity rather than in sperm output or function, although systematic population studies of the latter are difficult. Male ageing is associated with a progressive, partial and variable degree of androgen deficiency, but the clinical and public health significance remain to be established. Available evidence suggests that androgen supplementation is unlikely to prolong life expectancy but might improve quality of life through prevention of apparently age-related declines in androgen-sensitive tissues. The appropriate target population, treatment modality and objectives remain to be established by further controlled clinical studies.