A father’s extra pounds may be to blame for a heightened risk of autism in their children. A new population-based study found that there is a notable link between paternal obesity and an increased risk of several autism spectrum disorders in children.

The large study suggests that children who were born to obese fathers, not obese mothers, might have a higher risk of developing autism than children with slimmer fathers.

Researchers discovered that out of the approximately 93,000 Norwegian children they followed for the study, children who were born to obese fathers had twice the risk of developing autism. Nonetheless, the odds remained small. Slightly less than 0.3 percent of children were diagnosed with autism, compared to 0.14 percent of children whose fathers were of a normal weight.

The findings were published in the April 7 online edition of Pediatrics and were the first of their kind to link paternal obesity and the risk of autism.

Dr. Pal Suren, from the Norwegian Institute of Public Health in Oslo and lead study researcher, noted that there may be an “indirect” association.

Suren said that some gene variations may be responsible for both obesity and an increased risk of autism. He also explained that obese men may be more likely to be exposed to environmental factors that lead to autism.

However, Suren also suggested that there is a direct link to fathers who are obese, such as altered sperm quality.

Researchers did not find a strong link between obese mothers and child autism despite the fact that obesity was nearly the same in mothers and fathers in the study, at 9.6 percent and 10 percent, respectively.

These results are different from a 2012 study, which discovered that mothers who were obese before they became pregnant had a 67 percent increased chance of having children with autism spectrum disorders.

Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at Steven & Alexandra Cohen Children’s Medical Center of New York, said, “We had thought that maternal obesity may somehow be related to autism, but this is the first time anyone has looked at paternal weight, and the findings suggest we may have gotten it wrong.”