In vitro gametogenesis, the process of creating eggs or sperm from ordinary skin or blood cells, is not yet available for human reproduction and likely won’t be for at least a decade. The technology has produced live offspring in mice, but the leap to safe, reliable human application involves solving deep biological problems, passing years of safety testing, and navigating a regulatory landscape that doesn’t yet have a framework for it. Here’s where things actually stand.
What IVG Actually Involves
The basic idea is to take a cell from your body, reprogram it into a stem cell, and then coax that stem cell through the long chain of development that normally produces an egg or sperm. In a woman’s body, this process takes months and involves intricate hormonal signaling, structural support from ovarian tissue, and a special type of cell division called meiosis that halves the chromosome count. IVG attempts to replicate all of this in a dish.
The process requires cells to pass through a critical intermediate stage: primordial germ cell-like cells, or PGCLCs. These lab-made precursors faithfully mimic the earliest stages of natural germ cell development, but they cannot enter meiosis on their own. They only progress toward becoming actual gametes when combined with supporting cells from gonadal tissue. Even then, the cells must undergo a sweeping epigenetic reset, essentially erasing the molecular memory of being a skin cell and rebuilding the three-dimensional architecture of the genome from scratch. Research published in Nature shows that current lab-derived cells do not yet exhibit the same deep-level chromatin organization as natural germ cells, meaning the “reset” is still incomplete.
Where the Science Stands Today
Mice are the gold standard, and even there, the results are humbling. Japanese researchers first produced mouse pups from IVG-derived eggs in 2016, proving the concept works in mammals. But the process remains inefficient. Mature gametes generated in vitro frequently show abnormalities in how chromosomes divide during meiosis, which is the step that matters most for producing a healthy embryo. When things go right and embryos are transferred, live birth rates in mouse experiments hover around 37 to 50 percent, comparable to rates using conventional eggs. The pups born appear healthy and morphologically normal. That’s encouraging, but mice have far simpler reproductive biology than humans, shorter generation times, and decades of well-mapped genetics that make troubleshooting easier.
No one has yet created a fully mature, functional human egg or sperm cell from a reprogrammed skin cell. The startup Conception, based in the San Francisco Bay Area, claims to have gotten closer than any other group by successfully growing follicle-like structures (the ovarian compartments that nurture eggs to maturity) in the lab. The company has raised nearly $40 million and employs more than 40 people. A smaller company called Ivy Natal is taking a different approach, using CRISPR gene-editing to try to accelerate the stem-cell-to-gamete pathway. Neither company has published peer-reviewed results demonstrating a viable human egg.
Realistic Timeline Estimates
Matt Krisiloff, the founder of Conception, has speculated that the first human gametes derived in vitro could be achieved within a few years. But he has also acknowledged that those early cells would then require years of additional research and refinement before any human clinical trials could begin. That “years more research” caveat is critical: creating a cell that looks like an egg under a microscope is very different from proving it can safely produce a healthy child.
Before clinical trials could start, researchers would need to demonstrate that IVG-derived human eggs have normal chromosome counts, proper epigenetic patterning, and the ability to form embryos that develop normally through at least the early stages. They would also likely need extensive animal testing with primates, not just mice. A conservative reading of the field puts the earliest possible clinical use somewhere in the mid-2030s, and that assumes no major setbacks. Many reproductive biologists think a fully validated, widely available treatment is more likely 15 to 20 years away.
Who Would Benefit Most
IVG isn’t being developed just as an alternative to standard IVF. It targets people for whom current fertility treatments simply don’t work. The clearest group is cancer survivors whose eggs or sperm were destroyed by chemotherapy or radiation. This is especially relevant for children who undergo cancer treatment before puberty, since they have no mature gametes to freeze beforehand. For these patients, IVG could theoretically use a small skin sample taken before treatment to generate eggs or sperm years later.
Same-sex couples represent another major group. IVG could allow two men to have a biological child using an egg derived from one partner’s cells, or two women to have a child genetically related to both of them. People with primary ovarian insufficiency or complete absence of sperm production due to genetic conditions could also benefit, along with older individuals who have exhausted their natural egg supply and want a genetically related child without using donor gametes.
The Regulatory Gap
Even if the science succeeds, there is no clear legal pathway for bringing IVG to patients. In the United States, the FDA would oversee clinical trials, but Congress has for years blocked federal funding for research that creates or destroys human embryos, which complicates any government-supported trial. No specific regulatory framework for IVG-derived gametes exists yet.
In Europe, the situation is even more constrained. The EU Biotechnology Directive restricts patents on inventions involving human embryos for commercial purposes, and the European Court of Justice has interpreted this broadly to cover any entity with the potential to develop into a human being. Patents related to IVG techniques must also survive an ethical filter that prohibits inventions contrary to public morality, with human dignity serving as a powerful but unpredictable legal standard. The EU also imposes strict consent and compensation rules around the procurement and commercialization of human eggs, which would apply to IVG-derived eggs as well.
This means that even after the biology is solved, individual countries will need to decide whether IVG-derived reproduction is legal, how embryos created this way are classified, and what safety data is required before allowing clinical use. That regulatory process alone could add years.
Ethical Concerns Slowing Adoption
IVG raises ethical questions that go well beyond typical fertility treatments because it could, in theory, produce eggs and sperm in unlimited quantities. Today, IVF typically yields a handful of embryos per cycle. IVG could generate hundreds of embryos from a single patient, which dramatically changes the calculus around embryo selection.
Polygenic screening, where embryos are scored based on genetic risk for diseases or even traits like height and intelligence, already exists in limited form. Combine that with IVG’s potential for mass embryo production, and the concern shifts from theoretical to urgent. Bioethicists at the Hastings Center have warned that scoring embryos for non-disease traits opens the door to a form of privatized eugenics, where wealthier families could select for health advantages and even social traits that poorer families cannot access. The possibility of screening out normal human variation, rather than just serious disease, is a line many ethicists argue society is not prepared to draw.
There are also questions about consent and parentage. If eggs can be made from anyone’s skin cells, existing legal definitions of biological parenthood need revision. Some scenarios that IVG makes technically possible, like creating a child from a deceased person’s cells or from cells obtained without someone’s knowledge, have no legal precedent in most countries.
What to Realistically Expect
The most likely near-term milestones are the creation of a mature human egg or sperm cell in a lab, confirmed by independent researchers, followed by the formation of viable early-stage embryos for research purposes only. These steps could happen within the next three to five years based on current progress. Clinical trials involving embryo transfer and pregnancy are further out, probably not before the early to mid-2030s at the earliest, and initially limited to patients with no other reproductive options.
Widespread availability as a routine fertility option, something you could walk into a clinic and request, is likely 15 to 20 years away. The path from first human gamete to baby in arms is long, not because of a single technical barrier, but because of the sheer number of things that must go right: complete epigenetic reprogramming, normal meiosis, healthy embryo development, regulatory approval, and societal consensus on how the technology should be used.