Men too have a ticking “biological clock”—just like women—say scientists who have found that older fathers may put the health of their partners and unborn children at risk. The study, published in the journal Maturitas, which reviewed 40 years of research on the effect of parental age on fertility, pregnancy and the health of children.
Gloria Bachmann, from Rutgers University in the US, said, “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 realise their advanced age can have a similar impact.”
While the medical profession has no clearly accepted definition of when advanced paternal age begins—it ranges from 35 to 45—infants born to fathers over 45 have risen 10 percent in the US over the past 40 years, likely due to assisted reproductive technology.
The study found that men 45 and older can experience decreased fertility and put their partners at risk for increased pregnancy complications such as gestational diabetes, preeclampsia, and preterm birth.
Infants born to older fathers were found to be at higher risk of premature birth, late stillbirth, low Apgar scores, low birth weight, higher incidence of newborn seizures and birth defects such as congenital heart disease and cleft palate.
As they matured, these children were found to have an increased likelihood of childhood cancers, psychiatric and cognitive disorders, and autism.
Bachmann attributes most of these outcomes to a natural decline in testosterone that occurs with ageing, as well as sperm degradation and poorer semen quality, but she said that some correlations need more research.
“In addition to advancing paternal age being associated with an increased risk of male infertility, there appears to be other adverse changes that may occur to the sperm with ageing,” she said in a statement.
“Although it is well documented that children of older fathers are more likely to be diagnosed with schizophrenia—one in 141 infants with fathers under 25 versus one in 47 with fathers over 50—the reason is not well understood,” Bachmann said.
“Also, some studies have shown that the risk of autism starts to increase when the father is 30, plateaus after 40 and then increases again at 50,” she added.
