Alterations of fertility during male aging

The world-wide trend toward a longer life expectancy challenges societies with new socioeconomic problems. Different alterations in the aging male have been suggested, including changes in fertility. Although there are characteristic endocrine and morphological alterations of the aging testis, it is not clear whether these changes cause alterations in spermiogenesis, sperm parameters and function. Furthermore, paternal age-related influence on pregnancy rates has been discussed. This review of different aspects of the aging male relates to the key question of whether men undergo andropause or not. Characteristic morphological alterations in the aging testis are: reduction of the number of Leydig cells; increased deposition of lipofuscin, an age-related pigment in the Leydig cells; thickening and hernia-like protrusions of seminiferi tubules; thickening of the tunica albuginea and artherosclerosis-induced changes in testicular blood supply. These alterations relate to a decrease in total and free testosterone in aging males. However, no clear reduction in sperm parameters and sperm function tests has been reported, although aging may be related to a decrease in sperm motility. A negative influence of paternal age on pregnancy rates cannot be demonstrated, but an increase in structural chromosomal abnormalities of aging spermatozoa and a higher risk of autosomal dominant diseases in the offspring have been reported in relation to paternal age. Therefore, the American Fertility Society has recommended that semen donors should not be older than 50 years. Although there are characteristic alterations in the aging male, healthy men remain fertile during lifetime. An increasing paternal age is associated with a significantly higher genetic risk for the offspring. There is clearly no andropause comparable to menopause, however, further studies will be necessary to investigate additional age-related alterations and their possible consequences for aging men.