Babies born to fathers aged under 25 or over 51 have higher risk of autism, study claims

The age of the mother makes no difference

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There’s a lot of scaremongering around when women should and shouldn’t have babies. We’re told our biological clocks are ticking and if we don’t get pregnant by the time we’re 35, our fertility will fall off a cliff and we’ll never have children.

Men, however, haven’t been subjected to such scrutiny about when they’re fit to become fathers. Until now.

New research has found that babies born to fathers under the age of 25 or over 51 are at higher risk of developing autism and other social disorders.

The study, conducted by the Seaver Autism Center for Research and Treatment at Mount Sinai, found that these children are actually more advanced than their peers as infants, but then fall behind by the time they hit their teenage years.

The researchers analysed 15,000 UK-based twins aged between four and 16.

“Our results suggests that children born to very young or older fathers may find social situations more challenging, even if they do not meet the diagnostic criteria for autism,” said Magdalena Janecka, PhD, a fellow at the centre in Mount Sinai.

They found no link between the age of the mother and their offsprings’ social skill development.

“Our study suggests that social skills are a key domain affected by paternal age,” Dr Janecka said.

“What was interesting is that the development of those skills was altered in the offspring of both older as well as very young fathers.

“In extreme cases, these effects may contribute to clinical disorders. Our study, however, suggests that they could also be much more subtle.”

To find out whether the 15,000 children's social skills were affected by the age of their father was when they were born, the researchers looked for differences in the developmental patterns of social skills, as well as other behaviour, including conduct and peer problems, hyperactivity and emotionality.

They also separately investigated whether these effects of paternal age on development were more likely a result of genetic or environmental factors.

But after conducting genetic analyses, the researchers found that social skill development was mainly influenced by genetic rather than environmental factors, and those genetic effects became even more important as the age of the father increased.

“Our results reveal several important aspects of how paternal age at conception may affect offspring,” Dr. Janecka said.

“We observed those effects in the general population, which suggests children born to very young or older fathers may find social situations more challenging, even if they do not meet the diagnostic criteria for autism.

“Further, increased importance of genetic factors observed in the offspring of older, but not very young fathers, suggests that there could be different mechanisms behind the effects at these two extremes of paternal age.

“Although the resulting behavioural profiles in their offspring were similar, the causes could be vastly different.”

Dr Janecka believes the study’s suggested developmental differences are probably down to alterations in brain maturation.

“Identifying neural structures that are affected by paternal age at conception, and seeing how their development differs from the typical patterns, will allow us to better understand the mechanisms behind those effects of paternal age, as well as, likely, autism and schizophrenia,” she said.