Late-onset hypogonadism (LOH) is a situation where a middle-aged or older
man has low serum testosterone in conjunction with diffuse symptoms resembling
those of genuine male hypogonadism. Testosterone replacement therapy has become a
popular choice for the treatment of LOH. Aging is a process that includes irreversible
changes because of a large variety of endogenous and environmental factors. Paternal
aging also causes genetic and epigenetic changes in spermatozoa that damage male
reproductive functions through adverse effects on sperm quality and count, as well as
on sexual organs and also on the hypothalamic-pituitary testicular axis. If on one hand,
hormone production, spermatogenesis, and testes undergo changes as a man ages, on
the other hand, the offspring of older fathers show high prevalence of genetic
abnormalities, childhood cancers, and several disorders. Information on the impact of
age on male fertility is of growing importance, therefore, further studies should
investigate the onset of changes in the reproductive function and its effects on aging
men. The aim of this chapter is to briefly discuss the effects of aging on the male
reproductive system and function.
Keywords: Aging, Epigenetics, Infertility, Late-onset hypogonadism, Male
fertility, Oxidative stress, Paternal age, Replacement therapy, Semen parameters,
Spermatogenesis, Spermatozoa, Testes, Testosterone.
