Child's Risk When Older Sibling Has Autism
About 7 times higher odds seen for full-siblings in large Danish study, lower than other research
For his part, Biehler said the findings continue to support the idea that the causes of autism arise from many factors. "Their conclusions support the view that both genetic and environmental factors may contribute to the risk of younger children developing these disorders when their older brother or sister are known to have ASD," he said.
To study author Gronborg, the findings suggest that "nongenetic and environmental factors may play far greater roles than previously thought."
The higher risk seen for siblings born to the same mother compared to the fathers may indicate that obstetrical factors may be playing important roles in causing the disorder, both Biehler and Adesman said.
Parents who have a child with autism should discuss the findings with their health care provider, Biehler said.