In vitro gametogenesis: using induced stem cells to fertilize eggs

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.

IVF procedures fertilize eggs outside the body in a laboratory dish

In vitro fertilization is a complex and expensive set of procedures that potential parents dealing with infertility or genetic disorders may turn to when other methods are unavailable. IVF births account for 2% to 3% of all live births in the US annually.

Stem cells become specialized cells through the activation or silencing of specific genes

After fertilization, when a sperm cell fuses with an egg, the resulting stem cell is described as totipotent—capable of transforming into any type of body cell or embryonic structures (e.g., placenta). Once differentiated into multipotent cells, they can only specialize further within specific cell type families, such as hematopoietic cells that become platelets and red and white blood cells.

How to turn any cell of the body into a stem cell

Scientists have developed techniques allowing them to 'reprogram' any cell in the body into an induced pluripotent stem (iPS) cell, which can be used to create either more stem cells or specialized cells for use in experimental medical treatments. This page gives readers a brief introduction to the history of iPS cells, what researchers are studying with iPS cells, and challenges associated with iPS research.

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.

Follow an IVF procedure from lab to transplant

What happens once eggs are harvested from an ovary? How does an embryo form within a petri dish? This detailed video offers a glimpse of the transformations eggs experience as women age, and how sperm are injected into eggs in some forms of IVF treatment.

‘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.

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.)

Embryonic stem cells can develop into any other cell type in the body

Embryonic stem cells emerge around five days after fertilization, during the blastocyst stage of embryonic development. At this point, the embryo consists of about 100 to 150 cells and forms a hollow structure, and these cells are the ultimate source of all other cell types during fetal development.

'Artificial embryos': The hidden steps in forming a spine

Somitogenesis is the process by which segmented body structures like vertebrae form in embryos. While the process is well understood in animals like mice or zebrafish it is difficult to study in humans. But now, researchers have created a model of somitogenesis, using pluripotent stem cells, called an axioloid.

Scientists have demonstrated IVF to help critically endangered rhinos

Scientists have used the technique to create embryos from eggs harvested from captive southern white rhinos and implanted into a southern white rhino. They hope to use this proof of concept to eventually use IVF to revive the population of northern white rhinos, which are extinct in the wild and have no living males left, using a precious reserve of frozen embryos and a surrogate southern white rhino mother.

Mice were able to regenerate retinal cells in the lab—a breakthrough for mammals

Using gene therapy, a team of Korean researchers has enabled retinal regeneration in mice by blocking the intercellular transfer of a single inhibitory protein. This 2025 finding creates a new potential direction for treating retinal diseases. The work, which is still in animal studies, is projected to enter early-stage clinical trials in the next few years.

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

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

Selecting an embryo based on polygenic score is illegal in the UK, Israel, and swaths of Europe

Though their use for embryo selection is illegal in many locations, private clinics in the US may offer polygenic scores to inform embryo selection. The US Food and Drug Administration has not banned their use—instead the tests are regulated like supplements, meaning they are not regulated before they come to market but consumers can file complaints and then the agency may take action.

Gene therapy treats a disease by editing its DNA source

This modification is typically performed by viruses, which are naturally skilled at entering cells but have their disease-causing component removed before delivery. Once inside, cells can use the inserted genetic material to produce more helpful proteins, fewer harmful ones, or create new proteins.

Read about coral reef restoration efforts, from coral IVF and cryopreservation

Researchers have collected coral eggs and sperm from healthy reefs, grown baby corals in lab pools, and released them to help repopulate damaged or lost reefs. Devices such as Coralclip® help attach these corals to existing structures, promoting growth without the use of chemical bonding agents. Corals near extinction can be frozen using liquid nitrogen for future restoration efforts.

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

Research studies can be conducted inside or outside of living samples

While "in vitro" experiments occur outside living organisms for cost-effectiveness, "in vivo" experiments take place inside them, providing real-life insights at a higher cost and with increased ethical concerns. Alternatively, "in silico" methods use computational simulations.

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.

Organisms can possess multiple unique sets of DNA in one body

Genetic chimeras can result when cells with different DNA combine, such as when two sperm cells fertilize two egg cells, creating two embryos that then merge. In mosaicism, mutations arise within an organism after conception and can spread through cell division, resulting in diseases and forming genetically distinct anatomy.

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

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.

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.

Some female tardigrades reabsorb their eggs if no male fertilizes them

The eggs are laid in skin that has detached after molting. These species undergo sexual reproduction, but others reproduce asexually, with females producing clones from unfertilized eggs. Some hermaphrodite species have both male and female reproductive organs and can self-fertilize.

Why South Korean women are having fewer babies

For decades, Asian countries have been combating dwindling birth rates by basically bribing families into having more children: offering government-subsidized housing, free IVF treatments, and even straight-up cash handouts. It hasn’t worked. In this BBC video, a TV producer, a cartoonist, and a private-school teacher explain their views on having children in 21st-century Korea.

Microgravity environments improve the success of 3D bioprinting

Gravity can cause gaps, such as those in the chambers of a 3D-printed heart, to collapse before stem cells, hydrogels, and biochemicals bind together during the bioprinting process. Rather than Earth's surface, some bioprinting is done on the International Space Station, where defective organs are also printed to test treatment methods.

CRISPR technology is removing allergens from common foods

Proteins responsible for allergies to eggs, milk, wheat, peanuts, and other foods can be genetically edited out of foods to reduce the risk of life-threatening reactions. The technique has also been used to produce caffeine-free coffee beans, spicier tomatoes, allergen-free pets, and more nutritious fish.

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

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

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

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 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

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

See the evolution of Ebola vaccine and treatment development.

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.

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.

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

This site reaches millions of visitors who are tired of AI chatbots and seeking human connection. Pretend to be an AI chatbot and ask questions, provide answers, and draw for people in real time.

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

Venture capital is a form of funding provided to early-stage companies with high growth potential, typically in exchange for an equity (or ownership) stake

Play the role of a student in a game where you try to navigate college and remain debt-free, selecting different income levels, high school experience, race, ethnicity, and more.

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

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.

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

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

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.

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

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.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.