Conception Grows First Early Human Eggs From Stem Cells

Author: Ian C. Langtree - Writer/Editor for Disabled World (DW)
Published: 5 Jul 2026
Publication Type: Research, Study, Analysis

Table of Contents:
Synopsis - Definition - Introduction - Main - FAQ's - Insights, Updates - Related Publications

Synopsis: This article shares a research update from Conception announcing the creation of the first early human egg cells, known as primary oocytes, grown from stem cells rather than from donated tissue. Starting with an ordinary blood draw, the team reprogrammed blood cells into induced pluripotent stem cells and guided them into forming lab-grown mini-ovaries that house developing eggs. It offers a clear, accessible look at in vitro gametogenesis, a technology that could one day widen reproductive options for people facing infertility, women who wish to have children later in life, and individuals whose disabilities or medical conditions affect their fertility. For seniors and people with disabilities who follow progress in reproductive medicine, the piece translates complex laboratory science into plain language while remaining candid about the safety testing and further work still required before any clinical use.

At a Glance

• 1 - The approach avoids the hormone injections and surgical egg retrieval currently required for IVF.
• 2 - Researchers generate thousands of mini-ovaries at once, holding millions of future egg cells, and benchmark them against an internal atlas of human ovary data containing millions of datapoints.
• 3 - Conception reports making fully stem cell-derived follicles with eggs progressing through meiosis, which the company describes as a world first.

Topic Definition: In Vitro Gametogenesis (IVG)

In vitro gametogenesis, often shortened to IVG, is a laboratory process for creating reproductive cells such as eggs or sperm from ordinary body cells rather than from a person's own reproductive organs. It usually begins by reprogramming a common cell type, such as a blood or skin cell, into an induced pluripotent stem cell that can become almost any cell in the body, and then guiding those stem cells through the natural stages of egg or sperm development. In the context of this work, IVG is used to grow early human egg cells inside lab-built mini-ovaries, with the long-term aim of producing mature eggs for reproduction.

Introduction

The First Early Human Eggs From Stem Cells

Conception's mission is to turn stem cells into human eggs and redefine fertility.

We want to share an exciting update that we have generated the first early human egg cells ('primary oocytes') derived from stem cells. After performing a simple blood draw, we converted blood cells into stem cells, and then coaxed those stem cells into becoming miniature human ovaries that contain the early eggs. While there is still work ahead to grow these eggs to full maturity, we think this is a major scientific advance. - Conception

Main Content

Why This Matters

Making viable eggs from stem cells has already been accomplished in mice. In 2016, our collaborator Katsuhiko Hayashi demonstrated that mouse skin cells can be turned into 'induced pluripotent stem cells' (iPSCs, which are engineered cells capable of becoming any kind of cell in the body) and then turned into usable eggs. These eggs produced healthy pups that lived normal lifespans and reproduced naturally, having healthy pups of their own.

This process, known as "in vitro gametogenesis" (IVG), has been far easier to achieve in mice than in larger animals. Still, given how dramatically impactful this technology could be, it is well worth pursuing for human application.

IVG has the potential to redefine reproduction worldwide. From a simple blood draw, one could make as many healthy eggs as a family needs.

This capability could create freedom from biological and genetic limits. It could dramatically expand families' options for having healthy children and enable women to have children at a much older age– all without the hormone injections or surgical retrieval currently required for IVF.

The technology is one of the most complex therapies ever to be developed. We are not making just a single cell type; we are building entire mini-ovaries in the lab derived from stem cells, as the whole organ is important for proper egg development. We're excited that we've made hugely significant progress towards this goal, and we wanted to share a peek into our process.

Our Approach: Making Mini-Ovaries In The Lab

Conception's thesis is simple: there are no useful shortcuts. A cell that expresses a few egg markers is not enough. We need to rebuild, as closely as possible, the sequence that nature uses - and benchmark our cells against human development at every major step.

Our approach follows the major steps of egg development. After taking a blood sample, we turn a subset of blood cells into iPSCs, and then guide the iPSCs toward becoming each of the kinds of cells found in a developing ovary: 'primordial germ cells' are the cells that will eventually become eggs, and 'ovarian helper cells' are the supporting players that provide essential signals for the eggs. Together, these cells form 'mini-ovaries,' small 3-dimensional "balls of cells" that mimic a true human ovary.

In our research, we generate thousands of mini-ovaries, containing millions of future egg cells, to study, improve, and benchmark their development in parallel.

Inside the mini-ovaries, primordial germ cells are surrounded by the ovarian helper cells they need to begin moving through the next three stages of egg development:

1) The primordial germ cells progress toward 'oogonia'

2) The oogonia enter into meiosis, the special cell division needed to make eggs

3) As they become early egg cells, they form follicles, the essential ovarian units that house each egg

Along the way, we rigorously benchmark cell identity against a massive internally-assembled reference atlas of human ovary molecular data. This atlas includes millions of datapoints spanning a wealth of sequenced features capturing many layers of cell biology. Comparisons to this atlas (including with proprietary deep learning models) allow us to confidently chart our path forward biologically, while confirming the fidelity of our protocol and thus the quality of our cells.

One of the most important measures of success for us is function - can these cells faithfully perform the same roles of cells in a real ovary? We'll walk through how we benchmark that in each step below.

1) Our Mini-Ovaries Help Develop Future Eggs

An early sign of success for our mini-ovaries is that we see their organization closely mimics the structure of a developing human ovary. Oogonia form small "nests" – special ovarian structures surrounded by a thin boundary layer (in blue below) where future egg cells stay connected in groups and chains (in magenta). In the ovary, these structures help separate and organize developing egg cells, so seeing them form in our mini-ovaries is a sign that the tissue is developing the same way as it would in the human body.

2) Our Future Egg Cells Progress Through Meiosis

Most cells in our body contain two sets of chromosomes - one inherited from each parent - whereas egg cells contain only one. Meiosis is one of the defining events in egg development, and it's how the egg ends up with one set of chromosomes. It must happen with extraordinary precision because chromosomal mistakes can lead to failed pregnancies or genetic abnormalities.

Meiosis is one of the hardest things to get right. Chromosomes have to pair with their matching partners, exchange DNA, and (in the body) remain organized for decades. This is why the next result was so important to us: in our iPSC-derived cells, we see the machinery of meiosis assembling as it should.

A useful way to picture this process is as a zipper forming along each chromosome pair. In our cells, key structural proteins of the meiotic machinery load onto chromosomes in long, continuous tracks, consistent with the cells progressing through early meiosis.

We are not only looking at gene markers turning on but we see cellular machineries appearing in the right place and order, all in a system that is fully derived from stem cells.

We also see the broader molecular signatures expected as our cells transition toward early egg cells. We see key primary oocyte genes activate, including genes involved in egg growth, formation of the zona pellucida (the protective "egg shell" around the oocyte), and programs that help protect developing eggs.

Together, this all shows that our stem cell-derived cells are moving through meiosis and activating early egg cell genes as should be properly happening at this stage.

3) We Can Make Fully Ipsc-Derived Follicles

After entering meiosis, future eggs in the human ovary enter a long resting period. At this stage, the cell helps form a primordial follicle: one egg cell surrounded by a single layer of tightly connected support cells. This is the basic and most important unit of the ovary.

Generating fully stem cell-derived follicles, with early egg cells progressing through meiosis, is a major step toward making viable mature eggs. To our knowledge, this is a world first.

What's Next For Stem Cell-Derived Eggs

While we've come a long way, there is still more work to be done. The biggest remaining step for us is to grow our iPSC-derived follicles from the early stage (primordial) to the last "antral" step. At the antral stage, the oocytes have grown larger and are at the point where an IVF physician would collect them surgically. We believe this should be quite doable, as we have previously accomplished this with donated human tissue

Beyond that, our focus will be on validating the safety of our process and quality of our eggs. The bar for safety with this technology is incredibly high, and we take that responsibility very seriously. Before this work could be considered for clinical use, we need to deeply characterize each step of the process, both for existing progress and for fully mature egg cells in the future. This includes deeper animal model development and validation for safety as well.

Reprinted in part with permission from conception.bio For the complete study with associated images please visit https://www.conception.bio/science-and-updates/the-first-early-human-eggs-from-stem-cells

Frequently Asked Questions

NOTE: Researched FAQ's by Disabled World (DW)

How is in vitro gametogenesis different from conventional IVF?

Conventional IVF collects a woman's existing eggs after hormone stimulation and surgical retrieval, then fertilizes them in the lab. In vitro gametogenesis instead aims to create brand new eggs from stem cells derived from a blood or skin sample, so it does not depend on the eggs a person already has.

Can the same stem cell approach be used to create sperm?

In principle the induced pluripotent stem cell method can be guided toward either eggs or sperm, since the starting stem cells can become many cell types. This particular work focuses on producing early female egg cells, and sperm generation follows a separate developmental path.

Is in vitro gametogenesis currently approved for human reproduction?

No. The technology remains in the research stage, and the eggs described have not been matured or used to create a pregnancy. Extensive safety testing and regulatory review would be required before any clinical use in people.

How long before stem cell-derived eggs might be available to patients?

No firm timeline has been set. Researchers still need to mature the early follicles, confirm the eggs are safe and functional, and complete animal and preclinical studies, so practical availability is expected to be years away.

What ethical and regulatory questions does making eggs from stem cells raise?

Because the method could create eggs from almost anyone's cells, it raises questions about consent, genetic screening, access, and oversight. These issues are typically weighed by ethics boards and regulators alongside the scientific and safety evidence before any approval.

Insights, Analysis, and Developments

Author Credentials: Ian is the founder and Editor-in-Chief of Disabled World, a leading resource for news and information on disability issues. With a global perspective shaped by years of travel and lived experience, Ian is a committed proponent of the Social Model of Disability-a transformative framework developed by disabled activists in the 1970s that emphasizes dismantling societal barriers rather than focusing solely on individual impairments. His work reflects a deep commitment to disability rights, accessibility, and social inclusion. To learn more about Ian's background, expertise, and accomplishments, visit his full biography.