Xenotransplants are an experimental last resort for the terminally ill

After the patient died, a latent pig virus was discovered inside his xenotransplant

Researchers studying the death of David Bennett Sr., the first gene-edited pig heart transplant patient, discovered potential factors that may have contributed to his demise. One finding is that there was a latent virus, called porcine cytomegalovirus (PCMV), in the pig heart, which may have contributed to dysfunction of the transplant.

Pig-to-human transplants have raised concerns about pig living conditions

Pigs are the current first choice for xenotransplantation procedures, yet such work gives some researchers and animal welfare advocates pause. Concerns include that pigs would have a poor quality of life since the animals must live in a strictly-controlled, hyper-clean environment to avoid risky pathogens.

See different pig-to-human xenotransplantation possibilities

Xenotransplantation can include the insertion of any organ, tissue, cells or fluids from any nonhuman animal into a human. This US Food and Drug Administration graphic about pig-to-human applications shows different possibilities, including the exploration of using pig pancreatic cells for treating diabetes.

Chinese scientists transplanted a pig lung into a human being—but it had to be removed

In August 2025, Chinese scientists transplanted a pig lung into a brain-dead person, a common research step for this type of experimental work. Researchers used CRISPR technology to alter six proteins in the pig genes to make the organ seem less foreign to the human immune system. Within a day there were indications the organ wasn’t functioning well and that the person’s body was rejecting it. Scientists ended the experiment after nine days.

Read why one man agreed to get a pig kidney in 2025 to replace his own failing organ

The 68-year-old New Hampshire man told USA Today that a motivator for the experimental surgery was his belief that he was going to die anyway, and other people suffering from kidney disease could gain valuable insights. Yet the surgery bought him time—he lived 271 days with a pig organ and later received a human kidney transplant. Clinical trials began in 2026 to test the pig xenotransplants in more people.

Scientists may have discovered why gene-edited pig kidneys are rejected in humans

In November 2025, researchers studying how a brain-dead donor’s body responded to the transplantation of a genetically engineered pig kidney, published that they’ve identified immune system reactions that may explain why these pig organs get rejected. What’s more, they were able to reverse the rejections with an already available drug combination and the kidney functioned well. They also pinpointed a way to detect a potential rejection up to five days sooner.

Pig heart valves have been placed in humans since 1965

The first successful use of a pig heart valve in a human was reported in 1965. This 2015 video details why humans have been able to use pig animal valves for so long with good results and how that differs from what's needed for whole organ transplants.

A first-of-its-kind clinical trial taps livers from gene-edited pigs to clean blood

The experimental dialysis-like treatment from United Therapeutics, eGenesis, and OrganOx, is designed to help people with liver failure. The therapy, which involves attaching the modified pig liver externally, filters a patient’s blood so their own livers can temporarily rest and perhaps heal.

Cross-species transplantation has been attempted in medicine for more than 300 years

Early reported xenotransplantation attempts included 17th century efforts in France to transfuse blood from animals into humans. The poor results prompted France to issue a xenotransplantation ban. In the 19th century, researchers tried animal-to-human skin grafts from species including sheep, rabbits, dogs, cats, rats, chickens, and pigeons.

Pig organ transplants are apparently kosher—you just can’t eat them

Science writer Mary Roach speaks with journalist Terry Gross about her latest book, “Replaceable You: Adventures in Human Anatomy” and discusses topics including why pig organs have become of such interest and what religious leaders have told her about pig organs and compliance with Jewish dietary law.

In 1984, a dying infant lived for three weeks with a baboon heart

Pediatric-sized hearts are very hard to find. They're about the size of a walnut. When a premature baby girl was born with a fatal heart defect in 1984 her care team transplanted a 7-month-old baboon's heart into the patient. The organ was not genetically modified but still the infant lived for several weeks. This roughly hour-long documentary from the medical institution, features the patient's mother, clinician, and more discussing the controversial procedure and aftermath.

Global xenotransplantation market may already be valued at more than $13B

With more than 100,000 people on the waiting list for organs at any given time in the United States, there's a known demand for organ transplants. Some estimates put the value of the global xenotransplantation market above $13B in recent years—and project the market to continue growing.

How heart transplants work

Heart transplants require an old heart to be removed and a new one to be installed without killing the patient. How does that work? In this easy-to-understand five-minute video, learn each step of the intricate process, from donor matching to the preservative solution a heart is doused in while it is transported.

Living donations most commonly involve a kidney or part of a liver

In 2023, more than 6,900 transplants were made possible thanks to living donors. Living donation is when a living person donates an organ or part of an organ—usually one of their two kidneys or part of the liver, since that organ can regenerate in a healthy person. Much more rarely, living donors donate other organs. Living donations often occur when someone wants to ensure a loved one has certainty that they will quickly receive a needed organ.

Immunosuppressants enable organ transplants, but come with severe side effects

This drug cocktail helps to lower your body's natural response to attack a transplanted organ. Such medications usually need to be taken for a lifetime after receiving an organ and can come with serious side effects including high blood pressure, diabetes, increased risk of some cancers, and high cholesterol, among others.

As of 2025, perfect synthetic replication of natural organs remains elusive

Advancements such as 3D printing muscles, performing vaginal reconstruction with colon tissue, and growing organs in a lab have shown promise, but artificial options and transplanting substitutions continue to exhibit functional and performance limitations compared to their natural equivalents.

Research advances suggest death takes much longer than we realized

Recent research indicates that organs, including the brain, are better at handling a lack of oxygen after the heart stops beating than previously known. Such findings may open up possibilities that include someday reversing certain death processes and expanding the availability of organs available for organ donations. (Some users may experience a paywall.)

‘Hope for Healing’: The first-ever use of an in utero stem cell treatment

In 2023, researchers at UC Davis performed the first-ever fetal stem cell transplant, attempting to cure a case of spinal bifida prior to childbirth using stem cells derived from the placenta. The trial, and others including an effort to treat muscular dystrophy, highlight the potential power of stem cell therapy.

This scientist treated her own cancer

Virologist Beata Halassy treated her own breast cancer by injecting the tumor with lab-grown viruses. Though this self-treatment worked, it has not been approved for widespread use. Read to learn more about her fascinating experience, and how it has led to conversations about safety and ethics.

Fecal transplants can help treat infections

Fecal transplants aim to transplant healthy gut bacteria into ill patients by transferring (literally) samples of human waste from a healthy patient to a sick patient. The technique has been shown to cure otherwise deadly Clostridioides difficile (C. diff) infections and is being studied for a range of other uses.

The US FDA considered mitochondrial replacement therapy during 2014 hearings

An agency committee assessed if this approach could have undesirable ripple effects across multiple generations and whether a clinical trial involving this approach would be appropriate. As of 2026, the US has continued to prohibit this procedure though it is legal in other settings including the UK and Australia.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

Leonard Thompson was the first human to receive an insulin injection for diabetes

In January 1922, the 14-year-old was the first person to receive an insulin injection to treat diabetes, just months after insulin was isolated in dogs and used to treat their induced diabetes. Thompson had an allergic response to an apparent impurity in the injection, but his second dose, 12 days later, was a success.

Harvard drowned rats for this?

Harvard's 1950s rat study was ethically questionable, but scientifically profound. One rescue attempt made rats swim 40x longer. The finding: hope isn't poetic, it's biological.

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

Despite the rules, a Nobel Prize in medicine has been awarded posthumously

Ralph Steinman, whose work revealed how dendritic cells activate immune responses, passed away just days before being named a Nobel laureate. Although Nobel Prizes cannot be awarded posthumously, the committee made an exception because they believed he was alive at the time of the decision.

The last Pinta Island tortoise died in 2012 at over 100 years old

Unfortunately, different animal species continue to go extinct. See a list of these recent extinctions, and learn the story of Lonesome George, who died without finding a mate in the Galapagos Islands.

Read a deep dive on the 'all-purpose healing' peptide BPC-157.

Experimental hantavirus vaccines and therapies, still under development, have long been funded by the US military.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Astronauts have repaired genetic damage in space using CRISPR—a molecular tool that can make precise changes to DNA and is used in single-celled organisms to attack invasive viruses.

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

In 2018, 26-year-old missionary John Allen Chau was killed by tribesmen after attempting to reach and evangelize on India's isolated North Sentinel Island

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

The concept of phantom limbs, the perception that amputated limbs are still present, dates back to a French military surgeon in the 16th century.

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

Famed poet TS Eliot rejected the manuscript for George Orwell's political fable 'Animal Farm,' writing that its criticism of authoritarianism was not 'the right point of view.'

The tragic Pulitzer Prize-winning image 'The Vulture and the Little Girl' (1993) generated controversy, raised concerns about ethics in photography, and eventually led to the photographer's death.

Double world record holder Hunter Ewen helped conquer his fear of balloons, called globophobia, by training to win Guinness World Record titles for balloon inflation.

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.

After her fellow cult members tried to kill her with an LSD-infused hamburger, one member of the Manson Family, the murderous cult led by Charles Manson, decided to testify against the group's leader.

A vending machine run with Anthropic's AI went out of business after it was convinced to give away items for free and sell a video game console.

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

NBA superstar Victor Wembanyama spent the 2025 summer training with monks in central China to enhance his body and mind.

The use of fungi to detoxify land and water—a process known as mycoremediation—has been used to clean up natural resources affected by the 2025 California wildfires.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

In 1945, Surrealist artist Salvador Dalí and legendary animator Walt Disney began collaborating on a short film that was not completed until 2003, years after both men had died.

Brandi Chastain, the star of the 1999 US victory over China in the 1999 Women's World Cup, was a last-second choice to take the penalty kick that sealed the victory.

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.