Science
In search for autism’s causes, look at genes, not vaccines, researchers say
Earlier this year, Health and Human Services Secretary Robert F. Kennedy Jr. pledged that the search for autism’s cause — a question that has kept researchers busy for the better part of six decades — would be over in just five months.
“By September, we will know what has caused the autism epidemic, and we’ll be able to eliminate those exposures,” Kennedy told President Trump during a Cabinet meeting in April.
That ambitious deadline has come and gone. But researchers and advocates say that Kennedy’s continued fixation on autism’s origins — and his frequent, inaccurate claims that childhood vaccines are somehow involved — is built on fundamental misunderstandings of the complex neurodevelopmental condition.
Even after more than half a century of research, no one yet knows exactly why some people have autistic traits and others do not, or why autism spectrum disorder looks so different across the people who have it. But a few key themes have emerged.
Researchers believe that autism is most likely the result of a complex set of interactions between genes and the environment that unfold while a child is in the womb. It can be passed down through families, or originate with a spontaneous gene mutation.
Environmental influences may indeed play a role in some autism cases, but their effect is heavily influenced by a person’s genes. There is no evidence for a single trigger that causes autism, and certainly not one a child encounters after birth: not a vaccine, a parenting style or a post-circumcision Tylenol.
“The real reason why it’s complicated, the more fundamental one, is that there’s not a single cause,” said Irva Hertz-Picciotto, a professor of public health science and director of the Environmental Health Sciences Center at UC Davis. “It’s not a single cause from one person to the next, and not a single cause within any one person.”
Kennedy, an attorney who has no medical or scientific training, has called research into autism’s genetics a “dead end.” Autism researchers counter that it’s the only logical place to start.
“If we know nothing else, we know that autism is primarily genetic,” said Joe Buxbaum, a molecular neuroscientist who directs the Seaver Autism Center for Research and Treatment at the Icahn School of Medicine at Mount Sinai. “And you don’t have to actually have the exact genes [identified] to know that something is genetic.”
Some neurodevelopment disorders arise from a difference in a single gene or chromosome. People with Down syndrome have an extra copy of chromosome 21, for example, and Fragile X syndrome results when the FMR1 gene isn’t expressed.
Autism in most cases is polygenetic, which means that multiple genes are involved, with each contributing a little bit to the overall picture.
Researchers have found hundreds of genes that could be associated with autism; there may be many more among the roughly 20,000 in the human genome.
In the meantime, the strongest evidence that autism is genetic comes from studies of twins and other sibling groups, Buxbaum and other researchers said.
The rate of autism in the U.S. general population is about 2.8%, according to a study published last year in the journal Pediatrics. Among children with at least one autistic sibling, it’s 20.2% — about seven times higher than the general population, the study found.
Twin studies reinforce the point. Both identical and fraternal twins develop in the same womb and are usually raised in similar circumstances in the same household. The difference is genetic: identical twins share 100% of their genetic information, while fraternal twins share about 50% (the same as nontwin siblings).
If one fraternal twin is autistic, the chance that the other twin is also autistic is about 20%, or about the same as it would be for a nontwin sibling.
But if one in a pair of identical twins is autistic, the chance that the other twin is also autistic is significantly higher. Studies have pegged the identical twin concurrence rate anywhere from 60% to 90%, though the intensity of the twins’ autistic traits may differ significantly.
Molecular genetic studies, which look at the genetic information shared between siblings and other blood relatives, have found similar rates of genetic influence on autism, said Dr. John Constantino, a professor of pediatrics, psychiatry and behavioral sciences at the Emory University School of Medicine and chief of behavioral and mental health at Children’s Healthcare of Atlanta.
Together, he said, “those studies have indicated that a vast share of the causation of autism can be traced to the effects of genetic influences. That is a fact.”
Buxbaum compares the heritability of autism to the heritability of height, another polygenic trait.
“There’s not one gene that’s making you taller or shorter,” Buxbaum said. Hundreds of genes play a role in where you land on the height distribution curve. A lot of those genes run in families — it’s not unusual for very tall people, for example, to have very tall relatives.
But parents pass on a random mix of their genes to their children, and height distribution across a group of same-sex siblings can vary widely. Genetic mutations can change the picture. Marfan syndrome, a condition caused by mutations in the FBN1 gene, typically makes people grow taller than average. Hundreds of genetic mutations are associated with dwarfism, which causes shorter stature.
Then once a child is born, external factors such as malnutrition or disease can affect the likelihood that they reach their full height potential.
So genes are important. But the environment — which in developmental science means pretty much anything that isn’t genetics, including parental age, nutrition, air pollution and viruses — can play a major role in how those genes are expressed.
“Genetics does not operate in a vacuum, and at the same time, the impact of the environment on people is going to depend on a person’s individual genetics,” said Brian K. Lee, a professor of epidemiology and biostatistics at Drexel University who studies the genetics of developmental disorders.
Unlike the childhood circumstances that can affect height, the environmental exposures associated with autism for the most part take place in utero.
Researchers have identified multiple factors linked to increased risks of the disorder, including older parental age, infant prematurity and parental exposure to air pollution and industrial solvents.
Investigations into some of these linkages were among the more than 50 autism-related studies whose funding Kennedy has cut since taking office, a ProPublica investigation found. In contrast, no credible study has found links between vaccines and autism — and there have been many.
One move from the Department of Health and Human Services has been met with cautious optimism: even as Kennedy slashed funding to other research projects, the department in September announced a $50-million initiative to explore the interactions of genes and environmental factors in autism, which has been divided among 13 different research groups at U.S. universities, including UCLA and UC San Diego.
The department’s selection of well-established, legitimate research teams was met with relief by many autism scientists.
But many say they fear that such decisions will be an anomaly under Kennedy, who has repeatedly rejected facts that don’t conform to his preferred hypotheses, elevated shoddy science and muddied public health messaging on autism with inaccurate information.
Disagreements are an essential part of scientific inquiry. But the productive ones take place in a universe of shared facts and build on established evidence.
And when determining how to spend limited resources, researchers say, making evidence-based decisions is vital.
“There are two aspects of these decisions: Is it a reasonable expenditure based on what we already know? And if you spend money here, will you be taking money away from HHS that people are in desperate need of?” Constantino said. “If you’re going to be spending money, you want to do that in a way that is not discarding what we already know.”
Science
What’s in a Name? For These Snails, Legal Protection
The sun had barely risen over the Pacific Ocean when a small motorboat carrying a team of Indigenous artisans and Mexican biologists dropped anchor in a rocky cove near Bahías de Huatulco.
Mauro Habacuc Avendaño Luis, one of the craftsmen, was the first to wade to shore. With an agility belying his age, he struck out over the boulders exposed by low tide. Crouching on a slippery ledge pounded by surf, he reached inside a crevice between two rocks. There, lodged among the urchins, was a snail with a knobby gray shell the size of a walnut. The sight might not dazzle tourists who travel here to see humpback whales, but for Mr. Avendaño, 85, these drab little mollusks represent a way of life.
Marine snails in the genus Plicopurpura are sacred to the Mixtec people of Pinotepa de Don Luis, a small town in southwestern Oaxaca. Men like Mr. Avendaño have been sustainably “milking” them for radiant purple dye for at least 1,500 years. The color suffuses Mixtec textiles and spiritual beliefs. Called tixinda, it symbolizes fertility and death, as well as mythic ties between lunar cycles, women and the sea.
The future of these traditions — and the fate of the snails — are uncertain. The mollusks are subject to intense poaching pressure despite federal protections intended to protect them. Fishermen break them (and the other mollusks they eat) open and sell the meat to local restaurants. Tourists who comb the beaches pluck snails off the rocks and toss them aside.
A severe earthquake in 2020 thrust formerly submerged parts of their habitat above sea level, fatally tossing other mollusks in the snail’s food web to the air, and making once inaccessible places more available to poachers.
Decades ago, dense clusters of snails the size of doorknobs were easy to find, according to Mr. Avendaño. “Full of snails,” he said, sweeping a calloused, violet-stained hand across the coves. Now, most of the snails he finds are small, just over an inch, and yield only a few milliliters of dye.
Science
Video: This Parrot Has No Beak, But Is at the Top of the Pecking Order
new video loaded: This Parrot Has No Beak, But Is at the Top of the Pecking Order
By Meg Felling and Carl Zimmer
April 20, 2026
Science
Contributor: Focus on the real causes of the shortage in hormone treatments
For months now, menopausal women across the U.S. have been unable to fill prescriptions for the estradiol patch, a long-established and safe hormone treatment. The news media has whipped up a frenzy over this scarcity, warning of a long-lasting nationwide shortage. The problem is real — but the explanations in the media coverage miss the mark. Real solutions depend on an accurate understanding of the causes.
Reporters, pharmaceutical companies and even some doctors have blamed women for causing the shortage, saying they were inspired by a “menopause moment” that has driven unprecedented demand. Such framing does a dangerous disservice to essential health advocacy.
In this narrative, there has been unprecedented demand, and it is explained in part by the Food and Drug Administration’s recent removal of the “black-box warning” from estradiol patches’ packaging. That inaccurate (and, quite frankly, terrifying) label had been required since a 2002 announcement overstated the link between certain menopause hormone treatments and breast cancer. Right-sizing and rewording the warning was long overdue. But the trouble with this narrative is that even after the black-box warning was removed, there has not been unprecedented demand.
Around 40% of menopausal women were prescribed hormone treatments in some form before the 2002 announcement. Use plummeted in its aftermath, dipping to less than 5% in 2020 and just 1.8% in 2024. According to the most recent data, the number has now settled back at the 5% mark. Unprecedented? Hardly. Modest at best.
Nor is estradiol a new or complex drug; the patch formulation has existed for decades, and generic versions are widely manufactured. There is no exotic ingredient, no rare supply chain dependency, no fluke that explains why women are suddenly being told their pharmacy is out of stock month after month.
The story is far more an indictment of the broken insurance industry: market concentration, perverse incentives and the consequences of allowing insurance companies to own the pharmacy benefit managers that effectively control drug access for the majority of users. Three companies — CVS Caremark, Express Scripts and OptumRx — manage 79% of all prescription drug claims in the United States. Those companies are wholly owned subsidiaries of three insurance behemoths: CVS Health, Cigna and UnitedHealth Group, respectively. This means that the same corporation that sells you your insurance plan also decides which drugs get covered, at what price, and whether your pharmacy can stock them. This is called vertical integration. In another era, we might have called it a cartel. The resulting problems are not unique to hormone treatments; they have affected widely used medications including blood thinners, inhalers and antibiotics. When a low-cost generic such as estradiol — a medication with no blockbuster profit margins and no patent protection — runs into friction in this system, the friction is not random. It is structural. Every decision in that chain is filtered through the same corporate profit motive. And when the drug in question is an off-patent estradiol patch that has negligible profit margins because of generic competition but requires logistical investment to keep consistently in stock? The math on “how much does this company care about ensuring access” is not complicated.
Unfortunately, there is little financial incentive to ensure smooth, consistent access. There is, however, significant financial incentive to steer patients toward branded alternatives, or simply to let supply tighten — because the companies aren’t losing much profit if sales of that product dwindle. This is not a conspiracy theory: The Federal Trade Commission noted this dynamic in a report that documented how pharmacy benefit managers’ practices inflate costs, reduce competition and harm patient access, particularly for independent pharmacies and for generic drugs.
Any claim that the estradiol patch shortage is meaningfully caused by more women now demanding hormone treatments is a distraction. It is also misogyny, pure and simple, to imply that the solution to the shortage is for women’s health advocates to dial it down and for women to temper their expectations. The scarcity of estradiol patches is the outcome of a broken system refusing to provide adequate supply.
Meanwhile, there are a few strategies to cope.
- Ask your prescriber about alternatives. Estradiol is available in multiple formulations, including gel, spray, cream, oral tablet, vaginal ring and weekly transdermal patch, which is a different product from the twice-weekly patch and may be more consistently available depending on manufacturer and region.
- Consider an online pharmacy. Many are doing a good job locating and filling these prescriptions from outside the pharmacy benefit manager system.
- Call ahead. Patch shortages are inconsistent across regions and distributors. A call to pharmacies in your area, or a broader geographic radius if you’re able, can locate stock that your regular pharmacy doesn’t have.
- Consider a compounding pharmacy. These sources can sometimes meet needs when commercially manufactured products are inaccessible. The hormones used are the same FDA-regulated bulk ingredients.
Beyond those Band-Aid solutions, more Americans need to fight for systemic change. The FTC report exists because Congress asked for it and committed to legislation that will address at least some of the problems. The FDA took action to change the labeling on estrogen in the face of citizen and medical experts’ pressure; it should do more now to demand transparency from patch manufacturers.
Most importantly, it is on all of us to call out the cracks in the current system. Instead of repeating “there’s a patch shortage” or a “surge in demand,” say that a shockingly small minority of menopausal women still even get hormonal treatments prescribed at all, and three drug companies control the vast majority of claims in this country. Those are the real problems that need real solutions.
Jennifer Weiss-Wolf, the executive director of the Birnbaum Women’s Leadership Center at New York University School of Law, is the author of the forthcoming book “When in Menopause: A User’s Manual & Citizen’s Guide.” Suzanne Gilberg, an obstetrician and gynecologist in Los Angeles, is the author of “Menopause Bootcamp.”
-
Arkansas5 minutes agoEffort to cut former Arkansas corrections secretary’s position as adviser to governor fails – Arkansas Times
-
California11 minutes agoCalifornia sees lowest number of firearm-related deaths since 1968, new data shows
-
Colorado17 minutes agoSouthern Colorado farmers’ market season is here
-
Connecticut23 minutes agoAmtrak won’t close shoreline rail bridges during World Cup, reversing earlier proposal
-
Delaware29 minutes agoLucky Duck a new destination on the Delaware River waterfront
-
Georgia41 minutes ago2026 NFL Draft Scouting Report — Christen Miller, DT, Georgia
-
Hawaii47 minutes ago
Iran War Puts a Pause on Hawaii’s Housing Market Recovery
-
Idaho53 minutes agoIdaho Fish and Game reminds humans not to touch wild baby animals