Aging of the Male Germline: Influence of Advanced Male Age on Reproductive Outcome

Abstract

The rise in life expectancy and the desire to establish a stable career prior to parenthood leads couples to a delayed childbearing. Advanced parental age at the time of pregnancy portrays several risks, with the majority of couples above 35 experiencing reproductive impairments. While the effect of women's age on fertility is well known, the influence of paternal age is less understood. Thus, efforts have been made to comprehend the influence of APA on pregnancy upkeep and disease risk for the offspring. Over the last decades numerous studies aimed to establish the relationship between APA and male fertility potential. It has been found that APA is related to testicular and hormonal alterations, along with a decreased sperm production, quality and DNA integrity. As expected, these alterations compromise the reproductive potential of older men and have been associated with several fecundity problems, including increased time to pregnancy and abortion rates, and decreased fertilization and pregnancy rates. Additionally, alterations in offspring health, like genetic disorders, mental illnesses, congenital anomalies and cancer, have also been linked to APA. As a result, APA influence on the reproductive outcome must be taken into consideration when counseling couples attending family planning consultations or pursuing fertility treatments. Nonetheless, to date, there are still no definite results regarding this problem and an age threshold has yet not been established and additional research to better elucidate the effects of APA on fertility and offspring's health is needed. Likewise, establishing an age threshold for APA would be of great value to males thinking of delaying parenthood, and to physicians for medical advice purposes.