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In Vitro Gametogenesis: Eggs From Skin Cells

What if you could make an egg — or sperm — from any cell in your body? Scientists have already done it in mice. Here's what in vitro gametogenesis (IVG) means for the future of human reproduction, who it could help, and how far away it really is.

📅 Updated May 2026 ⏱️ 10 min read ✔ Medically reviewed
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The Quick Answer
In vitro gametogenesis (IVG) is an emerging technology that aims to create functional eggs and sperm from ordinary body cells — like skin or blood. It's been done successfully in mice, producing healthy offspring. In humans, researchers have created very early-stage precursors to eggs and sperm, but we're likely 10-15 years from clinical use. When it arrives, it could transform fertility treatment for everyone from cancer survivors to same-sex couples to women past menopause.
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What Is In Vitro Gametogenesis?

In vitro gametogenesis — IVG for short — is the process of creating sex cells (eggs and sperm, collectively called "gametes") in a laboratory, starting from cells that aren't reproductive cells at all.

Here's the basic idea: Take a small sample of cells from almost anywhere in your body — your skin, your blood, the lining of your cheek. Convert those cells into induced pluripotent stem cells (iPSCs), which are cells that have been "reprogrammed" back into a state where they can become virtually any type of cell in the body. Then, guide those stem cells through the precise developmental stages that normally produce eggs or sperm.

If it works in humans the way it already works in mice, the implications are staggering. Age wouldn't limit egg supply. Ovaries wouldn't be necessary for eggs. Testes wouldn't be required for sperm. Two men could have a child genetically related to both of them. A woman who lost her fertility to chemotherapy could regrow it from a blood sample.

IVG doesn't just push the boundaries of fertility treatment. It rewrites the fundamental rules of who can become a biological parent.

How It Works: From Skin Cell to Baby (in Mice, So Far)

The science of IVG builds on decades of stem cell research, but the breakthrough moments have been dramatic. Here's the simplified version of the process:

  1. Collect ordinary cells. Researchers start with somatic cells — non-reproductive body cells. In the landmark mouse studies, they used cells from the tip of a mouse's tail.
  2. Reprogram them into stem cells. Using a cocktail of genetic factors (a technique that won Shinya Yamanaka the Nobel Prize in 2012), the somatic cells are converted into induced pluripotent stem cells (iPSCs). These iPSCs are essentially reset to a "blank slate" state.
  3. Guide them toward becoming germ cells. Researchers coax the iPSCs to become primordial germ cell-like cells (PGCLCs) — the precursors to eggs and sperm. This involves carefully manipulating gene activity and growth conditions to mimic natural germ cell development.
  4. Complete maturation. This is the hardest part. To go from a primordial germ cell to a functional, mature egg requires an environment that mimics the ovary. In mouse experiments, researchers had to construct miniature artificial ovaries using ovarian support tissue. The proto-eggs needed to be incubated in these structures for weeks to fully mature.
  5. Fertilize and test. The resulting eggs are fertilized using standard IVF techniques and the embryos are transferred to a surrogate. In mice, this produced healthy pups that grew normally and went on to have their own offspring.
🎯 Why This Is So Hard in Humans

Mouse pregnancies last 20 days. Human egg development takes months. Each human IVG experiment could require an extended period to complete, making iteration painstakingly slow. And creating the artificial ovarian environment for human eggs is significantly more complex than for mice — we don't yet fully understand all the signals human eggs need to mature properly.

The Timeline: Where Are We Now?

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2012 — iPSC Nobel Prize
Shinya Yamanaka wins the Nobel Prize for discovering how to reprogram adult cells into pluripotent stem cells — the foundational technology that makes IVG possible.
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2016 — Mouse Eggs From Skin Cells
Katsuhiko Hayashi and Mitinori Saitou at Kyoto University create functional egg cells from mouse tail skin cells. After IVF and embryo transfer, the eggs produce healthy mouse pups — some of which go on to have their own offspring.
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2021 — Mouse Sperm From Stem Cells
Japanese researchers announce the first functional IVG-derived mouse sperm, which successfully produce live offspring. The sperm pathway is now proven alongside eggs.
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2023 — Two-Father Mice
Hayashi announces that his team has created mice with two biological fathers — generating viable eggs from male cells. This is the first time IVG-derived eggs have been made from the "opposite sex" cells.
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2024 — Human Precursors Achieved
Kyoto University researchers create precursors to human eggs and sperm (pro-oogonia and pro-spermatogonia) from human iPSCs — the most advanced human germ cells ever generated in a lab. These are far too immature to function as gametes, but they represent a major milestone in epigenetic reprogramming.
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~2030s — Human Eggs/Sperm From IVG?
Hayashi has estimated 5-10 years to create a human IVG egg mature enough to attempt fertilization. Most experts put clinical availability at 10-15 years from now — assuming safety testing, regulatory approval, and ethical frameworks keep pace with the science.

Who Could IVG Help?

If IVG becomes reality for humans, the list of people it could serve is broader than any existing fertility treatment:

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Women With Diminished Ovarian Reserve
Women who've run out of eggs — whether from age, premature ovarian failure, or genetic conditions — could have new eggs created from their own cells.
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Cancer Survivors
Chemotherapy and radiation often destroy fertility. IVG could restore it from a simple blood or skin sample, even years after treatment.
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Same-Sex Couples
Two men could have a child genetically related to both. Two women could conceive without donor sperm. This would fundamentally change LGBTQ+ family building.
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Unexplained Infertility
When the problem is egg or sperm quality that can't be otherwise fixed, IVG-derived gametes could bypass the issue entirely.
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Single Parents by Choice
In theory, IVG could allow a single person to create both eggs and sperm from their own cells — though this raises the most complex ethical questions.
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Genetic Conditions
Combined with genetic editing, IVG could allow couples carrying serious heritable conditions to produce gametes free of those mutations.

IVG vs. IVF: How They Compare

IVF (Today) IVG (Future)
Egg source Woman's own ovaries Any cell in the body
Requires ovaries? Yes (or donor eggs) No
Hormone injections 10-14 days of stimulation Not needed
Egg retrieval surgery Yes (transvaginal) Not needed
Limited by age? Yes — egg quality declines after 35 Potentially not
Number of eggs Typically 8-15 per cycle Theoretically unlimited
Available now? Yes — since 1978 No — estimated 10-15 years
Cost per attempt $15,000-$25,000 Unknown (likely very high initially)
📌 Important: IVG Wouldn't Replace IVF

Even if IVG produces viable eggs or sperm, those gametes would still need to be fertilized in a lab and the resulting embryos transferred to a uterus — using the same IVF techniques we use today. IVG solves the "raw materials" problem; IVF handles the rest. They'd work together.

The Ethical Questions We Need to Face

IVG doesn't just raise scientific challenges — it surfaces some of the most profound ethical questions in reproductive medicine. The fertility community, ethicists, and policymakers are already debating these:

Consent and Genetic Identity

If any cell can theoretically become a gamete, what does consent mean? Could someone create a child using another person's cells without their knowledge? Could a discarded tissue sample become the basis for reproduction? These aren't just theoretical concerns — they'll require entirely new legal frameworks around genetic consent and parentage.

"Solo" Reproduction

If a single person could generate both eggs and sperm from their own cells, they could technically have a child with only one genetic parent. The offspring would be a form of near-clone, inheriting two shuffled copies of one person's genome. This raises fundamental questions about genetic diversity, child welfare, and the social meaning of parenthood.

Embryo Overproduction

IVG could theoretically produce unlimited eggs, leading to the creation of vast numbers of embryos. Combined with genetic screening, this could enable selection among hundreds or even thousands of embryos — raising the specter of eugenics in a way that current IVF, limited by the number of eggs retrievable per cycle, does not.

Designer Babies

IVG alone doesn't edit genes. But combined with CRISPR or other gene-editing tools, the ability to produce unlimited gametes could make genetic "customization" of offspring technically feasible — even if it remains ethically and legally prohibited in most countries.

🔬 Expert Perspective: A February 2026 paper in Nature Biotechnology noted that IVG could redefine parentage itself, including the possibility of "bipaternal parentage." The authors stressed that while the science is advancing, IVG is not yet feasible for human reproduction, and the ethical and regulatory frameworks need to develop alongside the technology — not after it arrives.

The Safety Question

Even if IVG becomes technically possible in humans, proving it's safe is a separate — and enormous — challenge.

In the mouse experiments, while many of the offspring appeared healthy, the success rate was low. Not every IVG-derived egg or sperm produced a viable embryo, and not every embryo developed normally. The epigenetic reprogramming process — erasing and resetting the "memory" encoded in DNA — is delicate. Errors in this process could lead to developmental abnormalities, imprinting disorders, or health problems that might not appear until years or generations later.

Before IVG could be offered to human patients, researchers would need to demonstrate not just that it can produce a pregnancy, but that the resulting children — and their children — are healthy. Given the timeline of human development, this kind of multigenerational safety data would take decades to accumulate.

As one review in the journal Science put it: the use of IVG-derived gametes for human reproduction will require "careful legal and ethical discussions" well before clinical implementation.

What This Means for You Right Now

If you're currently trying to conceive or considering fertility treatment, IVG is not going to change your options today. The technology is firmly in the research phase for human applications, and clinical availability is likely more than a decade away.

What IVG does offer right now is hope for the future — particularly if you're facing a diagnosis like premature ovarian failure, azoospermia, or fertility loss from cancer treatment. The science is progressing faster than many predicted, and the leading research teams in Japan and the United States are well-funded and focused.

In the meantime, the technologies available today — IVF, egg and embryo freezing, donor gametes, and increasingly sophisticated genetic testing — are more effective than they've ever been. If you're not ready to start a family now, fertility preservation options can buy meaningful time.

Can't Wait for IVG? Explore Today's Options

IVF, IUI, egg freezing, and other treatments are available now. Our clinical guide breaks down each option with real costs and success rates.

Explore Fertility Treatments →

Further Reading

If this topic fascinates you (and honestly, how could it not?), these resources go deeper:

Frequently Asked Questions

In vitro gametogenesis is a technology being developed to create functional eggs and sperm from ordinary body cells like skin or blood. Scientists first convert these cells into induced pluripotent stem cells (iPSCs), then guide those stem cells through the developmental stages that normally produce eggs or sperm. The process has been successfully demonstrated in mice, producing healthy offspring, but has not yet been achieved in humans.
Most experts estimate IVG is at least 10-15 years away from clinical use in humans. As of 2026, researchers have created precursors to human eggs and sperm from iPSCs, but these are far too immature to be used for reproduction. Significant scientific, safety, and regulatory hurdles remain before IVG could be offered to patients.
In theory, yes. In 2023, Japanese researchers created mice with two biological fathers by making egg cells from male skin cells. If IVG could be perfected for humans, it could allow two men to have a genetically related child, or two women to conceive without donor sperm. However, this remains far from clinical reality.
No. IVF uses a woman's existing eggs, retrieved from her ovaries. IVG aims to create entirely new eggs or sperm from non-reproductive cells. If IVG is perfected, the resulting gametes would still need to be fertilized using IVF techniques — so IVG would complement IVF, not replace it.
Potentially. Since IVG creates eggs from stem cells rather than relying on existing ovarian reserve, it could theoretically produce fresh eggs at any age — even after menopause. This would be significant for women with diminished ovarian reserve, premature ovarian failure, or those who've undergone cancer treatment. However, many unknowns remain about the quality and safety of IVG-derived eggs.
IVG raises several ethical questions: the potential to create embryos without consent (since any cell could theoretically become a gamete), the possibility of "designer babies" if combined with genetic editing, concerns about solo reproduction (having a child with only one genetic parent), embryo overproduction, and the need for extensive safety testing. Regulatory frameworks for IVG are still being developed worldwide.

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Medical Disclaimer: This content is for informational purposes only and does not constitute medical advice. In vitro gametogenesis is an active area of research and is not currently available as a clinical treatment. Always consult with a reproductive endocrinologist for guidance specific to your fertility situation.