Parents with big age gaps ‘more at risk of having an autistic child’

COUPLES with a large age gap are more likely to have an autistic child, research suggests.

The study, involving millions of medical records, found mothers in their 30s with male partners who were ten or more years younger saw higher rates of the condition in their offspring.

Similarly, fathers aged between 34 and 44, with a female partner a decade or more younger, were more likely to have a child with autism than a couple without a big age gap.

The reasons for the link between a parental age gap and autism remain unexplained.

Even without an age gap, for fathers over 50 the risk of having an autistic child compared to men in their 20s was 66 per cent higher, the study found.

The scientists said the results are consistent with previous findings that show genetic deterioration of sperm quality in older men – which has been linked with autism risk.

The study also found teenage mothers were 18 per cent more likely to have autistic children than those in their 20s, while women giving birth in their 40s had a 15 per cent higher risk.

Study co- author Abraham Reichenberg, a neuropsychologist from the Icahn School of Medicine at Mount Sinai, New York, said: ‘ When we first reported that the older age of fathers increases risk for autism, we suggested that [genetic] mutations might be the cause ... In this study, we show for the first time that autism risk is associated with disparately aged parents.’

He said more research was needed to establish the cause.

People on the autistic spectrum often have difficulty com- municating and forming relationships. In Britain, around one in 100 children are diagnosed with autism spectrum disorder, while in the US the figure is one in 68.

The latest study is one of the largest ever autism research projects. It was based on analysis of 5.7million children born between 1985 and 2004 – of whom 30,000 have autism – in Denmark, Israel, Norway, Sweden and Western Australia.

Twins were excluded as they are known to have a higher risk of autism. Co-author Michael Rosanoff said there had been ‘confusion’ surrounding whether older mothers or fathers contributed to a higher prevalence of the condition, adding: ‘This shows both older mums and older dads share the autism risk.’

Attempting to explain why this could be, he said that people with the condition – which may be mild or undiagnosed – could take longer to find a partner.

Another one of the researchers, Sven Sandin, said: ‘Although parental age is a risk factor for autism, it is important to remember that, overall, the majority of children born to older or younger parents will develop normally.’

The study was funded by the US charity Autism Speaks. Research has consistently found that older fathers can raise the risk of certain illnesses in children, including mental health conditions such as schizophrenia.

Dr Judith Brown, of the UK’s National Autistic Society, said: ‘This is a substantial piece of research with a large sample size which adds to our understanding of the complex causes of autism.

‘ However, the study is not definitive ... there are a number of confounding variables which are not explained.

‘We therefore urge parents and those thinking of starting a family not to worry unduly about these research findings.’

More research is needed