Many of the new prenatal genetic tests for rare genetic conditions are inaccurate

Silicon Valley startups Orchid, Nucleus, and Genomic Prediction are selling so-called polygenic tests for prospective parents

These tests claim to show how at-risk a hypothetical baby would be for genetic syndromes. The newfound industry has prompted ethical and medical debates, with critics questioning their accuracy and highlighting the potential problems behind pursuing the perfect baby.

Pregnancy at older ages increases the chances of fetal abnormalities

Chromosomal irregularities are more likely at older maternal ages so genetic testing for a fetus of mothers-to-be at age 35 and older is often recommended. Conditions that can be screened for in utero include cystic fibrosis, Tay-Sachs disease, sickle cell disease, Down syndrome, spina bifida, Duchenne muscular dystrophy, and more.

Modern genetic testing stems from a 1950s discovery about the cause of Down syndrome

Scientists found that an additional copy of chromosome 21 causes the disease and developed an approach to stain chromosomes so they could be manually sorted and counted, which is called karyotyping. The breakthrough discovery by Marthe Gautier, a young French doctor and cytogenetics researcher, was appropriated by a male colleague, who listed himself as the lead author of the study reporting the finding.

The first prenatal screen for disease was developed in 1961

Scientist Robert Guthrie created a method to test newborns for a metabolic defect called phenylketonuria, or PKU. This blood test didn't look for gene variants—it hunted for excess phenylalanine in the blood. The disorder is caused by an inability to digest the amino acid phenylalanine, leading to excess phenylalanine in the body. PKU results in intellectual disability, seizures, and other symptoms if it isn't caught early and treated with a specialized diet.

Why genetic testing for Alzheimer's risk may not be right for you

Medical experts warn that completing Alzheimer's testing for late-onset versions of the disease can be fraught, in part because there's a shortage of genetic counselors to help navigate the findings and their potential implications, including for one's finances. Learning you have one or two copies of the APOE4 gene variant, which elevates Alzheimer's risk, can be panic-inducing, but an elevated risk for the disease is not the same as saying it definitely will develop.

Genetic tests aren't always actionable, which is one reason genetic counselors are so vital

This podcast interview with a Harvard Medical School professor focused on cancer genetics and prevention discusses the specifics of genetic testing and insights and the challenges of processing the outcomes of the testing and what may be actionable—or not.

At-home genetic testing results commonly led users to healthier lifestyles

Italian research that aimed to investigate what people do longer-term after receiving direct-to-consumer genetic test results indicated that whether the results were positive or negative, people tended to adopt a healthier diet after receiving the results, and they'd still maintained it a year after receiving their results. Some users also reported an overall reduction in stress over their health concerns. (Some users may encounter a paywall.)

Genetic drug matching, called pharmacogenomics, can help avoid dangerous drug reactions

Certain gene variants can affect how quickly or slowly medications are broken down in the body, affecting drug effectiveness and the risk of drugs failing. Such testing is often not covered by insurance companies though research indicates if these tests were performed for more than six drugs across the US population, avoided ailments would likely climb into the hundreds of thousands. (Some users may encounter a paywall.)

Polygenic scores aim to predict traits based on the contributions of many genes

These novel tests for multifactorial conditions evaluate the probability of traits like elevated blood pressure, diabetes, or high cholesterol based on what researchers currently know about different gene variants and their links to various traits. The tests are predictive, not definitive, partly because environmental factors influence the expression of genes. What's more, knowledge about cumulative effects from individual genes continues to evolve. The American Society for Reproductive Medicine states that these tests are too unreliable and nascent for clinical use.

The US FDA recently tried to regulate the expanded prenatal genetic tests

The agency proposed a new rule in 2023 to make it explicit that these types of tests are devices under existing law and clarify that that the agency could move to regulate them. They finalized a regulatory change in 2024 that added the words "including when the manufacturer of these products is a laboratory" to an existing law, but a federal district court vacated that edit in March 2025—returning the law to as it was before.

US regulators have approved an at-home genetic test looking for BRCA gene mutations

The direct-to-consumer genetic test, approved by US regulators in 2018, examines 3 out of the more than 1,000 known breast cancer-linked genetic mutations. It looks for genetic variations that can increase risk for breast, ovarian, and other cancers. These mutations are most commonly found among Jewish people with Eastern European ancestry.

Gene therapy, a hope of the Human Genome Project, saves a baby's life

A baby with a rare genetic disorder received a bespoke gene-editing treatment using CRISPR technology. The case highlights the potential of personalized medicine for rare diseases, building on the foundation set by the Human Genome Project.

Trials ongoing for a 99% accurate, AI-powered blood test

The UK's National Health Service has launched a trial for a blood test that can detect a dozen types of cancers with just ten drops of blood. An AI tool looks for genetic material known to be released by tumors, allowing for cancer detection before tumors are large enough to be imaged.

3-parent IVF removes most—but not all—faulty mitochondria

The process scoops out about 99% of the mother's mitochondrial DNA—replacing it with that of a donor woman—but because that roughly 1% is still in the system there is still a small chance of disease for the resulting child or future generations. (Some users may encounter a paywall.)

Carrier screening enables individuals without symptoms to see if they carry a gene for disease

Some conditions are autosomal recessive—meaning a person may carry a gene for that condition, but not have symptoms. Cystic fibrosis, sickle cell disease, and Tay-Sachs disease are examples of autosomal recessive diseases in which a person must inherit two copies of a nonfunctioning gene—one from each parent—to develop disease.

Home allergy tests don’t work well and experts urge caution

Doctors do not recommend at-home allergy test kits because their results may be inaccurate and confusing, and lead people to make lifestyle changes that are not warranted. Tests that require sending in a hair sample, for example, will not be helpful because hair does not have the relevant antibodies that blood testing would detect.

The lack of diversity in DNA databases limits their applications

European ancestry dominates genetic research, hindering the usage of genetic databases for precision medicine for other groups, including African Americans, who face higher health risks due to genetic variants. Many Indigenous communities have also resisted genetic research due to past exploitation. (Some readers may experience a paywall.)

The ultrarare 'Er' blood type has been documented only about 40 times

In 2022, the tragic loss of a pregnancy led researchers to the discovery that the rare "Er" blood type could potentially cause a mismatch in blood types between mother and fetus during pregnancy, with devastating consequences. (Some users may encounter a paywall.)

Modern pregnancy tests detect a specific hormone in a woman's urine or blood

They pick up human chorionic gonadotropin, in either blood or urine. The hormone is produced by a woman's reproductive tissues during pregnancy.

The spread of fraudulent stem cell treatments

All the coverage of research into promising (but often unproven) medical treatments involving stem cells has created conditions allowing some people to engage in activities regulators describe as scams. As this news article explains, attorneys general in at least seven states have taken legal action against businesses that promised (costly) stem cell treatments but allegedly engaged in fraud.

A pediatric journal ran 138 fictional case studies, and 61 were cited as real stories

The Canadian journal Paediatrics & Child Health issued corrections to 138 case studies published since 2000, acknowledging the cases were entirely fictional—a practice intended to protect patient privacy that was never disclosed to readers. At least 61 of the fabricated reports were cited as fact in other peer-reviewed journals a combined 218 times, including a 2006 Lancet article alleging an infant died from opioid-laced breast milk.

Alternatives to polygraphs, which correctly identify innocent people only 57% of the time

Lie detector polygraphs have been standard in law enforcement for a century despite being based in unproven science. Researchers are exploring brain-scanning and eye-tracking alternatives, though some suggest there's no reliable lie-detection process at all.

Find fertility clinics and their success rates in your state

This database from the Centers for Disease Control and Prevention provides a searchable portal of fertility clinics across the US, with reported data on services, total procedures performed, and live births recorded for as recently as 2022.

Blood tests for Lyme disease tend to come up as false negatives in the week after a bite

It can take several weeks for Lyme antibodies to develop, which is what blood tests would be detecting. That's why many clinicians will prescribe antibiotic treatment immediately after a bite if the individual develops the characteristic bullseye rash of Lyme or gets bitten in an area of the country known to have high rates of Lyme.

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

The 2026 Ebola outbreak is hampered by a lack of vaccine against the species of the virus, heightening the need for rapid tests to aid in disease control

Clinics in the Democratic Republic of Congo saw patients with Ebola symptoms months before the disease was identified. The identification lag was due to inadequate diagnostics that could not accurately or quickly identify the virus's myriad species. Contact tracing and better diagnostics will be required to tamp down the outbreak.

The 2026 Ebola outbreak is hampered by a lack of vaccine against the species of the virus, heightening the need for rapid tests to aid in disease control.

Telehealth demand for GLP-1s for weight loss is booming as consumers seek easier access.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

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

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

In recent years a child anxiety expert has created and tested a novel phobia and anxiety treatment approach for children, focused on changing how parents respond to the fears.

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

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

Netflix profits when you're not watching, and its movies are designed that way—read a detail-rich critical essay exposing lesser-known Netflix takes

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

Learn how to read a prospectus, the juicy document that any company must file with the SEC before going public.

A Yale student wrote a profound essay about the consulting industry's influence on elite college students that was published in a book of her writing after she died in a post-graduation car accident.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

Domino's Pizza's 30-minute delivery guarantee was responsible for the chain's 1980s surge, but it was discontinued after the company was found liable for delivery driver accidents.

The 1987 Nintendo video game 'Stadium Events' isn't known for being particularly fun, but its scarcity has made it a highly sought-after item that has sold for up to $35K at auction.

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

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

To reduce wrinkles in clothing, research recommends gentle wash cycles with more water and tumble drying with smaller loads and longer times.

Clever Hans was a 1900s horse that was believed to be able to solve math equations, tell time, and read and comprehend German, until a psychology student discovered how he got his answers.

See 33 images that became central to huge scandals, including a young Charles and Camilla, Michael Jackson's baby on a hotel balcony, and Hugh Grant's mugshot.

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