U.S. Health Secretary Robert F. Kennedy Jr. has pledged that the country’s top health agency will pinpoint the cause of autism by September, an announcement that sparked a wave of concern among medical experts and advocates, who question the feasibility and focus of the research.

Kennedy — a longtime vaccine critic who has pushed a discredited theory that routine childhood shots cause autism — said Thursday that the effort will involve hundreds of scientists. He shared the plans with U.S. President Donald Trump during a televised cabinet meeting.

Trump suggested that vaccines could be to blame for autism rates, even though decades of research have concluded there is no link between the two.

“There’s got to be something artificial out there that’s doing this,” Trump told Kennedy, later saying, “maybe it’s a shot. But something’s causing it.”

There’s scientific consensus that childhood vaccines don’t cause autism. Retreading this ground raises alarm bells, says Kristyn Roth, spokesperson for the Autism Society of America.

“There is a deep concern that we are going backward and evaluating debunked theories,” Roth told The Associated Press, adding that leading autism organizations have not been consulted about the planned research.

Autism is a developmental condition which presents a variety of symptoms that can include delays in language, learning and differences in social or emotional skills. Individuals with autism can also have a wide range of support needs. Around two per cent of Canadian children and youth are autistic, according to the Public Health Agency of Canada.

Decades of research, including studies on twins, have shown that genetics plays a large role in autism, but that there’s no specific “autism gene.” The U.S. National Institutes of Health, which already spends more than $300 million US yearly researching autism, also lists some possible risk factors such as prenatal exposure to pesticides or air pollution, extreme prematurity or low birth weight, certain maternal health problems or parents conceiving at an older age.

It’s “an exquisitely complex condition,” Dr. Melanie Penner, a senior clinician scientist and developmental pediatrician at Holland Bloorview Kids Rehabilitation Hospital at Toronto, told CBC News.

“Everything we know about autism suggests that this has a really complex, multifactorial origin that differs from child to child. So we need to invest in science that is capable of understanding that nuance, of understanding all of that complexity.”

Kennedy has offered no further details on how his study will be conducted, or what researchers will be involved.

It seems absurd to suggest that a single cause for a condition with such a strong genetic component could be found in a matter of months, says Paul Offit, director of the Vaccine Education Centre at the Children’s Hospital of Philadelphia. The reason Kennedy might see it as feasible, Offit suspects, is because Kennedy presumably believes he already knows the cause.

“He thinks vaccines cause autism. And no matter how many studies are done to show that he’s wrong, he doesn’t believe them,” said Offit, who is also a professor in pediatrics at the University of Pennsylvania School of Medicine.

Offit says he believes Kennedy’s end goal is to make vaccines “less available, less supportable and more frightening.”

“That’s what he’s doing, and to think otherwise is to not have paid any attention to who he is and what he has been doing for the last 20 years.”

Prior to Kennedy’s confirmation as U.S. health secretary, waves of health professionals urged senators to vote against the appointment — with one letter signed by more than 800 health experts highlighting that Kennedy’s lack of health expertise and “unfounded, fringe beliefs could significantly undermine public health practices.”

Rising rate of diagnoses

Trump and Kennedy have both expressed concerns about the rising rate of autism diagnoses, which Kennedy has called an “epidemic.”

But experts say diagnoses are up because of a broadening definition of autism, as well as efforts to increase awareness.

For decades, the diagnosis was given only to kids with severe problems communicating or socializing, and was thought to be very rare. But around 30 years ago, the diagnostic criteria was expanded as scientific understanding evolved to see autism as occurring on a spectrum. Milder autism cases are far more common than severe ones.

With improved screening and autism services, diagnosis is increasingly happening at younger ages, too. And more advocacy to combat “a long history of under recognition of autism in girls and women, gender diverse people and in racialized groups” has led to an increase in diagnoses in these groups, Penner said.

Still, anti-vaccine advocates, including Kennedy, have claimed that vaccines are to blame. The theory largely stems from a 1998 paper, in the medical journal The Lancet, that was later retracted as fraudulent.

Anne Borden King, co-founder of Autistics 4 Autistics: Self-advocacy in Canada, says it’s hugely stigmatizing when discussions about autism focus on a “cause” or a “cure.”

“We don’t want to be prevented. We want services that are actually useful for autistic people,” she said.

“My question, as an advocate, is how many more of these wild goose chases do we have to go on, when what we really could be doing is putting all those scientists to work, and all that research money to work, looking at research that actually improves the quality of life for autistic people that are here and now.”

Kennedy’s project is already off to a rocky start. The Department of Health and Human Services has hired David Geier, a man who was once fined by the state of Maryland for practising medicine on a child without a doctor’s license and has repeatedly claimed a link between vaccines and autism, to lead the federal research effort.

The department did not immediately respond to a request for comment.