The sibling of someone with autism has a 20% chance of developing ASD

Roughly 1 in 125 people have autism spectrum disorder globally

The disorder has been increasingly diagnosed as its definition has grown broader and as clinicians have become more adept at identifying it—with some estimates suggesting the figures are much higher. These figures include people across the spectrum, some of whom live mostly independent lives, while others require life-long care and assistance.

Risk factors linked with ASD include older parents, preterm births, and toxic prenatal exposures

Though researchers agree that there is a strong genetic component to ASD development, certain environmental factors heighten that risk, with studies suggesting older parents, premature birth, maternal obesity, and air pollution exposure in utero all elevate risks of ASD development. There is no connection between receiving vaccines and ASD development.

1 in 31 kids in the US has autism

That figure comes from an analysis published by the US Centers for Disease Control and Prevention based on data gathered on eight-year-olds in 2022. Its figures mark a significant increase from 2000, when the estimated autism figure was one in 150, but improvements in diagnosis and changes to the disease criteria that broadened the diagnostic criteria are widely believed to be driving that increase.

Even if you have some ASD-linked gene variations you may not develop ASD

Individual environment and life experiences affect how genes perform in the body, potentially adding methyl groups to DNA that affect their function and turning genes on and off—which may heighten or reduce disease risk.

Autism occurs among women, too

Males have higher rates of diagnosed autism than females, but recently scientists and people with autism have been exploring if females have been disproportionately missed in screening and if girls are perhaps masking their symptoms better, leading to missed diagnoses.

Autism rate increases are mostly among those with milder symptoms, not individuals with severe symptoms

Broader case definitions and better screening are typically now detecting more milder cases of autism rather than individuals who have severe impairments (who could be categorized as having profound autism). Profound autism rates, an autism researcher says in this article, have stayed proportionately steady.

80% of schizophrenia cases may be inherited

Some research suggests that anywhere between 60% and 80% of people with schizophrenia had genes that predisposed them to the syndrome. That high rate has fueled interest in further exploration of what environmental and lifestyle factors cause some people with that genetic risk to develop the disease when others with the same genetic risks do not.

Twin studies suggest celiac disease is among the more genetically-linked disorders

Genetics appear to play a larger part in this condition's development than many other autoimmune disorders. Research shows a roughly 60-75% genetic probability that if one identical twin has it, the other will too. Celiac triggers a small intestine attack when people eat gluten, a protein commonly found in wheat, barley, and rye.

A growing number of autism researchers with the disorder are reshaping the field

People with autism are now leading research on the effects of stigma and discrimination and promoting more studies on public services for autistic people. They also serve as editors, reviewers, and board members on autism academic journals, creating a new chapter in a field littered with painful stereotypes and prejudice.

Gene expression patterns are similar between ASD, schizophrenia, and bipolar disorder

Postmortem brain tissue analysis suggests there are genetic and epigenetic similarities between individuals with autism, schizophrenia and bipolar disorder. All three conditions appeared to have activation of genes in astrocytes and suppression of specific genes that function at the junction between neurons, called synapses. (Some users may encounter a paywall.)

Autism and ADHD may have overlapping symptoms and someone can have both disorders

This video explores similarities and differences between these two disorders, which both have genetic causes. Challenges with attention, hyperactivity, and impulsivity are typical of ADHD. Fidgeting, problems picking up on social cues, emotional dysregulation, and being oblivious to time may occur with both disorders—though the impetus for these behaviors may differ.

Many patients with psoriasis develop other autoimmune diseases, too

A small study published in 2024 found that nearly three-quarters of patients with psoriasis—a condition in which the body attacks healthy skin cells—also developed autoimmune disorders including thyroid diseases, connective tissue diseases, and more, suggesting such connections between these autoimmune disorders warrant further exploration.

Here’s why genetically identical sisters can have different colored eyes

The sequence of DNA that we inherit from our parents encodes directions for making our cells and giving us specific traits. Identical twins have the same DNA sequence, so how can one twin end up with a genetic disorder while the other twin does not? Robin Ball explains how the secret lies in X chromosome inactivation.

Bill Nye did not have children for fear of passing on ataxia

In his 2017 documentary, Nye revealed the congenital, neurological condition on his father's side of the family, which is characterized by a lack of balance and problems with fine motor movement. He has since learned he likely does not have the disease, though both his siblings have shown symptoms.

Some men may be at elevated risk of inheriting tinnitus

A 2017 Swedish Twin Registry study suggests that bilateral tinnitus—when tinnitus occurs in both ears instead of just one—appears to be heritable, at least in men.

Genetics may account for nearly 67% of mosquito attractiveness

In a mosquito attraction study published in 2015, identical twins appeared equally attractive to mosquitoes in lab tests, whereas some nonidentical twins were far less likely to be bitten than their siblings. Other work related showed that body odor is also more similar between identical twins.

Extremely rarely, there can be twins with different dads—but fewer than 20 such cases are documented worldwide

The non-identical twins, who would also be half-siblings, result from a rare biological phenomenon called heteropaternal superfecundation. Britain's first known twins with different dads, featured in this article, learned of each other's existence in recent years, when they were both 45. They discovered each other after taking DNA tests from Ancestry, a genealogy company.

Five to ten percent of Alzheimer's cases are early-onset

Early-onset Alzheimer’s typically emerges around 40 to 50 years of age, with devastating effects. This video follows Brian, diagnosed with the disease at age 54, as he travels the country as an advocate for research and discusses the progressive mental fog of Alzheimer’s.

Amish kids have far fewer allergies than the general population

Only about 7% of Amish children in a northern Indiana community have tested positive for common allergens in routine skin prick tests, whereas half of the general US population tests positive for them. Asthma is also extremely uncommon among the Amish, even when compared with other farming communities. Researchers are interested in exploring if approaches like exposing kids across the general population to Amish farm dust might stave off some allergies.

Fertility treatments linked to increased risk of cancer among offspring

Recent research has explored potential links between increased childhood cancer occurrence, particularly leukemia, and assisted reproductive technology (ART). Though some studies have detected this type of association, researchers caution that it remains unclear if ART itself, fertility drugs, underlying infertility of the parents, or other unknown factors may explain any increased cancer numbers among ART-conceived children. Overall, the incidence of cancer in children, regardless of conception method, is very low.

Trauma is a primary risk factor for substance use disorder later in life

Studies indicate 75% of people with substance use disorder have experienced at least one traumatic experience in their life. These experiences alter brain function, leading to heightened stress and emotional pain. Substances offer temporary relief, but this often results in dependency.

Tetrachromacy allows humans to observe 10 times the normal amount of colors

Resulting from a mutation on the X chromosome, the rare genetic condition causes individuals to possess an additional type of photoreceptor cell, typically sensitive to the orange range, located between the standard red and green cones. This enables the perception of approximately 100 million colors.

Salvador Dalí believed he was his own dead brother

Dalí's parents found the miracle of his birth nine months after his brother died to be profound, telling him he was his brother's reincarnation. Dalí carried this belief into his adult life and often cited its deep influence on him, including his preoccupation with death and mortality.

Individuals typically spend less time with others as they get older

At younger ages, we spend much of our time with parents, siblings, and friends. Eventually, our lifestyle changes to include work, a spouse, and children of our own. In later life, children often move out, and spouses unfortunately pass away, leading to more time spent alone.

Special needs trusts help financially care for dependents with disabilities

Special needs trusts are a specific type of trust that ensures dependents with special needs still qualify for Supplemental Security Income and Medicaid, given the trust's assets are excluded from the asset limits tests required to qualify for these programs.

Salvador Dalí believed he was his own dead brother, who had died nine months before he was born

About 12.5% of US adults experience a phobia in their lifetime, a diagnosis that hinges on the intense fear interfering with daily life and persisting for at least six months.

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

About 2,000 US babies are born annually without some portion of their limbs, potentially leading to a lifetime of pricey prosthetics.

US housing costs have risen by roughly 175% between 1991 and 2026—but a growing number of Gen Zers are becoming homeowners anyway. In 2025, 4% of homebuyers were Gen Z, up from 3% the year before.

Use this tool to calculate the dollar value of your parental mental load, from meal planning to coordinating after-school care, then see resources that help generate solutions.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

Firework or sparkler burns, even if they cover a relatively small area of skin, can significantly affect our range of motion.

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

Poison ivy's rash-causing compound is found in the plant's roots, stem, and leaves—so coming into contact with any part of the plant can lead to rashes for the 85% of people who are allergic to it.

SpaceX's S-1 or 'prospectus' revealed many previously unknown details about the company, including its unprofitability despite doing $18.7B in revenue in 2025, exactly how many voting shares Elon Musk will have in the company (roughly 85%), and more.

Children are now three times more likely to say they want to be a YouTuber when they grow up than an astronaut, with some even attending 'YouTube camps' that teach kids how to create content for the platform.

Coral polyps reproduce via broadcast spawning, where entire reefs simultaneously release reproductive cells for about one hour, once a year.

Up to a million Girl Scouts sell about 200 million cookie boxes every spring, generating $800 million, largely because refusing a child is frowned upon

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Dozens of S&P 500 stocks, including Coca-Cola and Walmart—known as the dividend aristocrats—have increased dividends every year for 25 years

English mathematician Ada Lovelace wrote the first computer algorithm a century before computers existed and hypothesized that computing devices would one day be able to compose music—foreseeing the generative AI systems of today.

The Brothers Grimm were lawyers before they were storytellers, but became interested in fairy tales as they began investigating how rules and customs had been passed down through cultures.

Louisiana's 'Cancer Alley' is infamous for having some of the highest industrial pollution, toxic air emissions, and cancer risks in the US.

Browse a detailed visual analysis of over 200,000 similes—comparisons that often use 'like' or 'as'—from popular fiction to see how frequently writers the same idiomatic expressions.

The United States is one of only around two dozen countries with a fully federal system of government, in which power is divided between national and state governments.

Ebola species have historically been named after where they were discovered, stigmatizing residents who live there, including Bundibugyo, in Uganda.

See how Budweiser's famous Clydesdales spend their days at Warm Springs Ranch, where roughly 70 to 80 of the beer brand's giant horses can be found at any given time.