What Is In-Vitro Gametogenesis (IVG)?

In-vitro gametogenesis (IVG) is an emerging area of reproductive science that aims to create human egg and sperm cells in the laboratory from non-reproductive cells, such as skin or blood cells. While still experimental, IVG is widely regarded as one of the most potentially transformative — and ethically complex — developments in fertility research.

The basic concept

Under normal circumstances, humans produce gametes (eggs and sperm) through specialised cells in the ovaries and testes. IVG seeks to replicate this process outside the body.

The approach typically involves three main steps:

1. Cell reprogramming: Adult somatic cells (for example, skin cells) are reprogrammed into induced pluripotent stem cells (iPSCs). These cells behave similarly to embryonic stem cells and can theoretically develop into any cell type.

2. Germ cell formation: The iPSCs are then guided, using carefully controlled chemical and biological signals, to become primordial germ cell-like cells — the precursors of eggs or sperm.

3. Maturation into gametes: These precursor cells are further matured into egg or sperm-like cells, either entirely in the laboratory or using supportive biological environments designed to mimic the ovary or testis.
   

In animals, particularly mice, IVG has already resulted in viable offspring. In humans, however, research has not progressed beyond early laboratory stages.

Why IVG matters

If proven safe and effective, IVG could fundamentally change fertility medicine.

Potential applications include:

• Helping people who cannot produce eggs or sperm due to age, genetics or medical treatment such as chemotherapy

• Allowing same-sex couples to have genetically related children

• Offering new reproductive options for people with certain forms of infertility

• Enabling deeper scientific understanding of how human eggs and sperm develop

IVG could also, in theory, allow women to generate large numbers of eggs at any age, challenging long-standing biological limits on fertility.

Current state of the science

Human IVG is not clinically available and remains firmly in the research phase.

So far:

• Scientists have produced egg- and sperm-like cells from human stem cells in the lab

• Some of these cells show molecular and structural similarities to natural gametes

• In limited experimental settings, egg-like cells have been fertilised to form very early embryos, which are not implanted and are destroyed in accordance with legal and ethical rules
  

Crucially, researchers do not yet know whether lab-derived human gametes could safely lead to healthy pregnancies or children. Issues such as genetic stability, abnormal development and long-term health risks remain unresolved.

Ethical and regulatory questions

IVG raises significant ethical, legal and social questions, which is why regulators are paying close attention even at this early stage.

Key concerns include:

• Safety: the risk of genetic or epigenetic abnormalities

• Consent and oversight: who controls the creation and use of lab-made gametes

• Embryo creation: the possibility of producing large numbers of embryos

• Social implications: changes to concepts of parenthood, age limits and reproduction
  

In the UK, any clinical use of IVG would require new legislation or regulatory approval from the Human Fertilisation and Embryology Authority (HFEA). Similar regulatory hurdles exist worldwide.

Relationship to other fertility breakthroughs

IVG is often discussed alongside innovations such as:

• Stem-cell-derived ovarian or testicular support cells

• Egg maturation outside the body

• Artificial womb and embryo culture technologies
  

Together, these advances point towards a future where reproduction may rely less on the body and more on laboratory-based processes — though that future is still many years away.

What comes next

Most experts agree that clinical use of IVG in humans is at least a decade away, if it happens at all. The near-term value of IVG is likely to be in research, helping scientists better understand infertility, early development and genetic disease.

For now, IVG remains a powerful idea rather than a medical option — one that sits at the intersection of cutting-edge biology, ethics and society’s evolving views on reproduction.