Do Men Have a 'Biological Clock' for Conception?

While the link between age and fertility is usually reserved for women, a new study suggests that men should also consider their "biological clock" when planning to have children. Led by researchers from Rutgers University and published in the journal Maturitas, the study outlines how age is often associated with fertility problems in men. Furthermore, the study also suggests that older dads can run the risk of endangering the health of their children.

The study reviewed 40 years of research exploring the link between older fathers and incidents of premature birth, stillbirth and newborn seizures. The research also noted factors such as low birth weight and birth defects like cleft palates and congenital heart disease. As the children matured, the study noted higher risk of mental health problems, childhood cancers, autism and cognitive disorders.

New study explored risks of “advanced paternal age”

While the researchers couldn't pinpoint exactly when “advanced paternal age” becomes an issue, they did reveal that it can emerge anywhere between the ages of 35 and 45. “While it is widely accepted that physiological changes that occur in women after 35 can affect conception, pregnancy and the health of the child, most men do not realize their advanced age can have a similar impact," explains Gloria Bachmann, study author and director of the Women's Health Institute at Rutgers' Robert Wood Johnson Medical School.

Despite the risks associated with advanced paternal age, the study notes that in the US the number of children born to fathers aged 45 or over has increased by 10% over the past 40 years. The team explain this is likely due to social changes, as well as improvements in assisted reproductive technology.

Decline in testosterone and sperm quality cited as potential cause

Bachmann and her colleagues didn't investigate why advanced paternal age can lead to wider health problems, though the team did cite several factors that could explain the apparent link. The first is the natural decline in testosterone that most men undergo during the ageing process. Quality of sperm was also referenced, with sperm stem cells continuing to split and divide around 23 times a year after a man hits puberty. As DNA gets copied this increases the risk of potential coding errors and mutations which can be passed on to children.

“Just as people lose muscle strength, flexibility, and endurance with age, in men, sperm also tend to lose 'fitness' over the life cycle,” asserts Bachmann.

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