WASHINGTON (AP) — Health secretary Robert F. Kennedy Jr. warned that children in the U.S. are being diagnosed with autism at an “alarming rate,” promising on Wednesday to conduct exhaustive studies to identify any environmental factors that may cause the developmental disorder.

His call comes the day after the Centers for Disease Control and Prevention released a report that found an estimated 1 in 31 U.S. children have autism, a marked increase from 2020.

Autism experts applaud efforts to further understand the condition, but say the number of reported cases began to balloon as the definition of the condition expanded to include mild cases.

“Autism destroys families," Kennedy said. "More importantly, it destroys our greatest resource, which is our children. These are children who should not be suffering like this.”

Kennedy described autism as a “preventable disease,” although researchers and scientists have identified genetic factors that are associated with it. Autism is not considered a disease, but a complex disorder that affects the brain. Cases range widely in severity, with symptoms that can include delays in language, learning, and social or emotional skills. Some autistic traits can go unnoticed well into adulthood.

Those who have spent decades researching autism have found no single cause. Besides genetics, scientists have identified various possible factors, including the age of a child’s father, the mother’s weight, and whether she had diabetes or was exposed to certain chemicals.

Kennedy said his wide-ranging plan to determine the cause of autism will look at all of those environmental factors, and others. He had previously set a September deadline for determining what causes autism, but said Wednesday that by then, his department will determine at least “some” of the answers.

The effort will involve issuing grants to universities and researchers, Kennedy said. He said the researchers will be encouraged to “follow the science, no matter what it says.”

The Trump administration has recently canceled billions of dollars in grants for health and science research sent to universities.

The CDC’s latest autism data was from 14 states and Puerto Rico in 2022. The previous estimate — from 2020 — was 1 in 36.

Boys continue to be diagnosed more than girls, and the highest rates are among children who are Asian/Pacific Islander, American Indian/Alaska Native and Black.

To estimate how common autism is, the CDC checked health and school records for 8-year-olds, because most cases are diagnosed by that age. Other researchers have their own estimates, but experts say the CDC’s estimate is the most rigorous and the gold standard.

On Wednesday, Kennedy criticized theories that the rise in autism cases can be attributed to more awareness about the disorder. Autism researchers have cited heightened awareness, as well as medical advancements and increased diagnoses of mild cases.

“The reasons for increases in autism diagnosis come down to scientific and health care progress,” said Annette Estes, director of the autism center at the University of Washington. "It's hard for many people to understand this because the causes of autism are complex.”

The Autism Science Foundation said Kennedy’s emphasis on environmental factors contradicted the findings in the CDC’s report.

“This report is the most convincing evidence yet that changes in factors like access to services and de-stigmatization of (autism spectrum disorders) are leading to the increases in prevalence,” said Autism Science Foundation Chief Science Officer Dr. Alycia Halladay.