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

Without 3-parent IVF, women carrying faulty mitochondrial DNA have few options for children

Women who are carriers of mitochondrial diseases that wish to have children without those conditions cannot be biological parents without three-parent IVF. The alternatives are to adopt or have a child via egg donation.

3-parent baby approach may help women with infertility

Though the topline promise of this approach is avoiding passing on mitochondrial diseases, some researchers and companies have been eyeing its potential for helping with female infertility, since faculty mitochondria may contribute to the condition. Recent research suggests this approach could be promising.

Eight British children have been born via mitochondrial replacement therapy

In July 2025, a decade after British lawmakers signed off on allowing three-parent IVF, scientists announced that eight healthy babies had already been born using this approach. The news was included in a pair of research articles published in a peer-reviewed journal that noted the oldest kids were already more than two years old, and that they were hitting developmental milestones as expected. (Some users may encounter a paywall.)

Four frozen embryos in the US were created via 3-parent IVF technique

Columbia University researchers created four embryos using mitochondrial replacement therapy for four female patients who didn't want to pass on mitochondrial diseases to their children. Yet US law restricts the researchers from implanting the embryos so they remain frozen. (Some users may encounter a paywall.)

Mitochondrial DNA swapping can occur before or after fertilization

Mitochondrial replacement therapy can be conducted with four different techniques, with varying genetic material transferred depending on the approach. Maternal spindle transfer, one common method, involves transplanting the nuclear DNA from a mother into an unfertilized egg from a donor. The donor egg is then fertilized and implanted into the mother's uterus using in vitro fertilization. Another major approach, pronuclear transfer, does the genetic swapping after the mother's egg has already been fertilized. This order of operations may be uncomfortable for some individuals, but the success rate with this technique is higher.

See how to make a baby with 3 parents, a process called mitochondrial replacement therapy

This primer video dives into the science of mitochondrial disease risks, how this controversial mitochondrial replacement technique can work, and why proponents say this reproductive advance—already legalized in the UK and Australia—is needed in the United States.

CRISPR can't fix faulty mitochondria

Gene editing via CRISPR could theoretically fix many issues in biology, but editing the mitochondrial genome has remained challenging. In recent years, there has been some progress reaching these cellular powerhouses. (Some users may experience a paywall.)

Australia legalized 3-parent IVF in 2022

It was the second country, after the UK, to legalize the procedure, which is still prohibited in the US. There are more than 300 rare mitochondrial diseases that can be passed from a mother to her offspring.

How to consider the ethics of 3-parent IVF, which is illegal in the US

Ethical concerns with this controversial procedure include that a little bit of a child's offspring would be from a third person and that the decisions made with this pregnancy will affect numerous generations, making a permanent change to the gene pool.

Mitochondria—only inherited from mothers in most animals—have their own DNA

Mitochondrial DNA, or mtDNA, typically takes the shape of a circle and contains genes that code for proteins essential to the production of energy-containing molecules called ATP. When mitochondria fuse, the mixing of healthy and damaged mtDNA helps alleviate the effects of mutations that may have occurred during mitochondrial division or environmental interactions.

See this 201-level explanation about mitochondria and mitochondrial replacement therapy

This 2022 academic presentation from Stanford University's Dr. Gregory Enns offers a detailed overview about mitochondrial therapy approaches. Enns, a pediatric geneticist, explains how well-functioning mitochondria support the human body.

How two families navigated an unthinkable IVF mistake

The field offers hope to thousands of families annually, but it is also largely unregulated, and for a small number of parents, things can go terribly wrong.

Scientific advances are unlocking a wide range of alternatives to IVF

From refined artificial insemination and microsurgical sperm extraction to experimental uterine transplants, scientific innovation is rapidly advancing potential fertilization technologies. But they come along with costly trials, some ethical dilemmas, regulatory issues, and more.

Roughly 1 in every 4,300 individuals in the US has mitochondrial disease

Roughly 1,000 to 4,000 kids are born with these conditions each year in the US though many of the diseases are fatal. Mitochondrial disorders often affect the organs that require the most energy, including the heart, brain, and muscles.

How personalized gene-editing saved a baby's life

KJ Muldoon had a 50% chance of surviving a genetic mutation until doctors developed a one-of-a-kind gene-editing therapy. In an interview with one of the researchers behind the treatment, learn what it will take to make personalized genetic medicine possible for everyone.

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

Established screening tests for Down syndrome in utero are reliable and accurate. But a New York Times investigation into expanded prenatal genetic tests for very rare diseases—much rarer than Down syndrome—found that more than 80 percent of the positive test results turned out to be wrong based on follow-up testing. These expanded tests for rare diseases are performed from a blood draw at 10 weeks of pregnancy and aim to detect chromosomal abnormalities linked to rare diseases. Companies that offer these controversial tests counter that it's only a screening test—not a diagnosis—picking up true positives and noting that patients can and should be counseled about what the findings mean. (Some users may encounter 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.

About 70% of the Human Genome Project's reference genome came from one donor

Volunteers who donated blood to the Human Genome Project consented to using no more than 10% of their DNA, raising questions about the project's legality. Listen to how pressure from a private competitor may have driven officials to ignore ethical standards.

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

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

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

How to repair a baby’s broken heart

A rare disorder that prevents some babies from getting enough oxygen to their organs can be repaired through a series of three intricate surgeries. This article and graphic explain the process behind correcting single-ventricle defects, also known as SVDs.This disorder happens when one of the heart's lower chambers doesn't work correctly, resulting in deoxygenated and oxygenated blood circulating the body rather than just the latter.

Here’s how different genetic disorders get passed on

The human genome is complex, as identified by the Human Genome Project. This article digs in to genetic disorders, the most common ones, and how they are diagnosed.

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.

Only about 0.0001% of sperm, on average, successfully reach the uterine cavity

We've evolved to make pregnancy a complex and difficult process. From the initial development of the blastocyst, to the energy and nutrients needed to grow a new human, our bodies are both fighting and supporting fetal development.

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.)

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.

The woman erased from the DNA breakthrough

Rosalind Franklin captured “Photo 51,” the key to DNA’s double helix. Her data, shared without her knowledge, helped Watson and Crick win a Nobel. She never got the prize, but today, her role in unlocking life’s blueprint is finally recognized.

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.

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.

Against his wishes, Albert Einstein's brain was removed before his cremation, and the pathologist responsible stored it for decades in mason jars within a beer cooler.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

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.

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

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

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

Apollo astronauts left items in the moon's 'toss zone,' including golf balls, family photos, and bags of human waste, to make room for lunar rocks.

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.

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.

Tattoos remain visible on your skin thanks to immune cells called macrophages

Explore the archaeological treasures of Pompeii, the city buried under volcanic ash when Mount Vesuvius erupted in 79 CE.

Marburg virus, related to Ebola, is also extremely deadly, and has no available vaccine.

When you complete a CAPTCHA on a website to prove you are human, you may be unknowingly training algorithms for self-driving cars, whose systems require training data to help identify crosswalks, bicycles, and other outdoor objects.

The original copy of the Declaration of Independence is not a pristine document, and even features a smudged anonymous handprint in the bottom left corner.

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.

Massive 3D printers have been used to build homes by stacking layers of 'concrete toothpaste,' a fire-resistant material that effectively insulates against outside noise.

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.

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.

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.