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

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.)

The first child born via mitochondrial replacement therapy was born in 2016

The healthy baby boy's mother carried genes for a rare mitochondrial disease called Leigh syndrome and after multiple miscarriages the family opted to try the controversial procedure. It was conducted by a US doctor in Mexico. The procedure is prohibited in the United States.

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.

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.

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.

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.)

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.

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.

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.

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.)

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.

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.

3-parent baby technique fuels worries of future 'designer babies'

Some critics of this approach worry that any genetic manipulation will both culturally and technologically normalize the idea of "designer babies"—embryos that are manipulated or selected based on physiological characteristics including height, eye color, athletic ability, and intelligence.

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.)

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.

Using artificial wombs to improve preterm infant health outcomes

Researchers at a hospital in the US have successfully used artificial wombs to care for preterm lambs and are now looking at the possibility of human trials. This nine-minute video includes interviews with the researchers and explains the reasoning...

‘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.

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.

One dad, one hundred babies

A look at the companies offering surrogacy to the ultrarich—including Chinese men taking their reproductive cues from Elon Musk.

Why humans evolved single-child pregnancies

While birthing twins has been a rare occurrence for humans, research suggests that twins were actually the norm much further back in primate evolution. It’s proposed that single-childbearing turned out to be critical for the evolution of larger babies with larger heads. Discover more about the shift that gives insight into primate evolution.

Medical professionals have experimented with using mixed reality headsets

Devices like the Apple Vision Pro have helped doctors develop surgical plans for hip and knee replacements using software that provides 3D models and other tools. Virtual screens displayed by mixed reality devices can provide information related to surgical progress, a patient's vitals, and more.

Turning nuclear waste into cancer medications

This video explores Terrapower, a company transforming nuclear waste into lifesaving cancer treatments. This is accomplished through the production and use of Actinium 225, a rare isotope derived from thorium, which is used in targeted alpha therapy to treat cancer.

Why don't we synthesize blood?

We're trying. Scientists are currently working on creating viable synthetic blood, an alternative to the presently relied-upon donations that manage to fall short of demand. More than half of the world's nations struggle to meet their population's need for blood. This article details current and historical efforts to develop synthetic blood, a venture that started more than 400 years ago.

France once had a reproduction czar to help midwives deliver babies

Much ado is made about falling marriage and birth rates worldwide, and how they might affect tax bases, retirement funds, and social standing. But this isn’t the first time marriage, and subsequently reproduction, have fallen out of favor. Some countries have resorted to drastic measures to restore the tarnished state of these hallowed institutions.

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

Mifepristone, approved in 2000, is used to end early pregnancies

The drug works by blocking progesterone, a hormone that is needed to support pregnancy. Mifepristone is typically used in combination with a second drug, misoprostol, because this regimen often causes less cramping and bleeding than just using misoprostol alone.

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

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

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.

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

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.

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.

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.

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.

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

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.

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.

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

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.

Watch how deep-sea mining equipment collects and processes polymetallic nodules—metal-rich, potato-shaped rocks—from the ocean floor and creates environmentally damaging plumes of sediments.

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

See images of medical cases of firework injuries shared on this 'Instagram for doctors.' (Warning: Graphic content)

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

The history of many kitchen appliances involves unexpected discoveries and applications, including wartime radar turned hamster defroster and replacing an 'ice king' with heat-stealing boxes.

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

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

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by more than 1.5 million Muslims each year.

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.

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