While female fertility comes to an end at menopause (at an average age of 51 years), men do not have similar biological senescence. Studies have shown that sperm counts may decline and DNA damage in sperm cells may increase over time, but the celebrity fatherhood of aging actors and rock stars perpetuates the myth that male fertility might last forever.
However, the published evidence does show that men are indeed regulated by a biological clock. Studies have demonstrated a decline in natural male fertility and an increase in miscarriage rate as men get older. So far it is not yet known whether paternal age affects outcomes in IVF and intracytoplasmic sperm injection (ICSI), or if there is (or should be) any age limit to treatment.
A recent analysis of almost 5,000 IVF/ICSI cycles performed at a single center in London indicates that success rates do decline significantly after a paternal age of 51 years. Miscarriage rate in this study was not affected by the age of the male partner. Nevertheless, the investigators confirm that paternal age over 51 does significantly affect the chance of success in assisted reproduction, adding that this warrants a call for “a public health message for men to not delay fatherhood,” said Dr. Guy Morris, from the Centre for Reproductive and Genetic Health in London.
“In the context of this emerging evidence for the deleterious effect of increasing paternal age, our data certainly support the importance of educating men about their fertility and the risks of delaying fatherhood,” he said. This study was observational and not designed to investigate any biological explanation for its findings. However, Dr Morris said that the data “suggest that semen quality decreases with increasing age and that this decline mirrors the decline in IVF outcome which we found.”