Latest news with #KatsuhikoHayashi
News18
07-07-2025
- Health
- News18
Birth Without Pregnancy: Lab Eggs And Sperm Closer To Reality Than You Think
Last Updated: In-vitro gametogenesis (IVG) could allow humans to create eggs and sperm from skin or blood cells within 5 to 7 years, revolutionising reproduction and challenging norms What was once the stuff of futuristic fantasy is now on the verge of becoming a reality. Scientists around the world are racing to develop in-vitro gametogenesis (IVG) — a revolutionary technology that could allow humans to create eggs and sperm from skin or blood cells, potentially enabling childbirth without traditional pregnancy. At the forefront of this scientific frontier is Professor Katsuhiko Hayashi of Osaka University, Japan, whose lab is pushing the boundaries of what we know about human reproduction. The Promise Of IVG: A New Era Of Parenthood In an interview with The Guardian, Professor Hayashi revealed that his lab could produce fully functional human eggs and sperm in just seven years. This means a future where: A woman gives birth without ever being pregnant Two men become biological fathers A person creates a child using only their own DNA While this may sound like science fiction, it's fast becoming a scientific possibility. Global Race To Revolutionise Fertility Japan isn't the only country investing in this bold future. In the United States, Conception Biosciences, a Silicon Valley startup led by Matt Krisiloff, claims their lab-based fertility solutions could reach clinics in as little as five years. Armed with significant funding, their aim is not just to treat infertility but to reshape the very idea of family and reproduction. In a landmark mouse experiment, researchers successfully created a female mouse using the sperm of two males, a proof-of-concept that's now being translated to human biology. IVG begins with stem cells derived from human skin or blood. In Professor Hayashi's lab, scientists have created tiny testicular and ovarian organoids — 1 mm sized structures that mimic real reproductive organs. These lab-grown organs are already producing precursor sex cells, though challenges remain in sustaining their growth. Current hurdles include ensuring oxygen supply, cell stability, and avoiding genetic defects. Another breakthrough includes the development of ovary organoids, which are now capable of progressing toward full human egg development. What The Future Holds: Hopes And Controversies If successful, IVG could radically alter options for people struggling with infertility or those traditionally excluded from biological parenthood. It opens the door for: But with innovation comes uncertainty. IVG raises serious ethical, legal, and religious questions. Issues of genetic health, societal acceptance, and long-term effects remain largely unanswered. Global Status And Ethical Landscape Currently, IVG is banned in the UK, though the US and Japan continue to fund and accelerate research. Professor Saito of Kyoto University and several American startups, including Conception Biosciences, are actively competing in this rapidly evolving space. While the timeline is uncertain, experts believe that within a decade, the first child born from lab-made eggs or sperm could become a reality, marking a profound shift in how we understand human life. First Published: July 07, 2025, 12:25 IST
The Guardian
05-07-2025
- Science
- The Guardian
Lab-grown sperm and eggs just a few years away, scientists say
Scientists are just a few years from creating viable human sex cells in the lab, according to an internationally renowned pioneer of the field, who says the advance could open up biology-defying possibilities for reproduction. Speaking to the Guardian, Prof Katsuhiko Hayashi, a developmental geneticist at the University of Osaka, said rapid progress is being made towards being able to transform adult skin or blood cells into eggs and sperm, a feat of genetic conjury known as in-vitro gametogenesis (IVG). His own lab is about seven years away from the milestone, he predicts. Other frontrunners include a team at the University of Kyoto and a California-based startup, Conception Biosciences, whose Silicon Valley backers include the OpenAI founder, Sam Altman and whose CEO told the Guardian that growing eggs in the lab 'might be the best tool we have to reverse population decline' and could pave the way for human gene editing. 'I feel a bit of pressure. It feels like being in a race,' said Hayashi, speaking before his talk at the European Society of Human Reproduction and Embryology's (ESHRE) annual meeting in Paris this week. 'On the other hand, I always try to persuade myself to keep to a scientific sense of value.' If shown to be safe, IVG could pave the way for anyone – regardless of fertility or age – to have biological children. And given that Hayashi's lab previously created mice with two biological fathers, theoretically this could extend to same-sex couples. 'We get emails from [fertility] patients, maybe once a week,' said Hayashi. 'Some people say': 'I can come to Japan.' So I feel the demand from people.' Matt Krisiloff, Conception's CEO, told the Guardian that lab-grown eggs 'could be massive in the future'. 'Just the aspect alone of pushing the fertility clock … to potentially allow women to have children at a much older age would be huge,' he said. 'Outside of social policy, in the long term this technology might be the best tool we have to reverse population decline dynamics due to its potential to significantly expand that family planning window.' In a presentation at the ESHRE conference, Hayashi outlined his team's latest advances, including creating primitive mouse sperm cells inside a lab-grown testicle organoid and developing an human ovary organoid, a step on the path to being able to cultivate human eggs. IVG typically begins with genetically reprogramming adult skin or blood cells into stem cells, which have the potential to become any cell type in the body. The stem cells are then coaxed into becoming primordial germ cells, the precursors to eggs and sperm. These are then placed into a lab-grown organoid (itself cultured from stem cells) designed to give out the complex sequence of biological signals required to steer the germ cells on to the developmental path to becoming mature eggs or sperm. Inside the artificial mouse testes, measuring only about 1mm across, Hayashi's team were able to grow spermatocytes, the precursors of sperm cells, at which point the cells died. It is hoped that an updated testicle organoid, with a better oxygen supply, will bring them closer to mature sperm. Hayashi estimated that viable lab-grown human sperm could be about seven years away. Sperm cultivated from female cells would be 'technically challenging, but I don't say it is impossible', he added. Others agreed with Hayashi's predicted timescale. 'People might not realise how quickly the science is moving,' said Prof Rod Mitchell, research lead for male fertility preservation in children with cancer at the University of Edinburgh. 'It's now realistic that we will be looking at eggs or sperm generated from immature cells in the testicle or ovary in five or 10 years' time. I think that is a realistic estimate rather than the standard answer to questions about timescale.' Prof Allan Pacey, a professor of andrology and deputy vice-president of the University of Manchester, agreed: 'I think somebody will crack it. I'm ready for it. Whether society has realised, I don't know.' While several labs have successfully produced baby mice from lab-grown eggs, creating viable human eggs has proved far more technically challenging. But a recent advance in understanding how eggs are held in a dormant state – as they are in the human ovary for more than a decade – could prove crucial. In the race to crack IVG, Hayashi suggested that his former colleague, Prof Mitinori Saitou, based at Kyoto University, or Conception Biosciences, which is entirely focused on producing clinical-grade human eggs, could be in the lead. 'But they [Conception] are really, really secretive,' he said. Krisiloff declined to share specific developments, but said the biotech is 'making really good progress on getting to a full protocol' and that in a best case scenario the technology could be 'in the clinic within five years, but could be longer'. Most believe that years of testing would be required to ensure the lab-grown cells are not carrying dangerous genetic mutations that could be passed on to embryos – and any subsequent generations. Some of the mice born produced using lab-grown cells have had normal lifespans and been fertile. 'We really need to prove that this kind of technology is safe,' said Hayashi. 'This is a big obligation.' In the UK, lab-grown cells would be illegal to use in fertility treatment under current laws and the Human Fertilisation and Embryology Authority is already grappling with how the safety of lab grown eggs and sperm could be ensured and what tests would need to be completed before clinical applications could be considered. 'The idea that you can take a cell that was never supposed to be a sperm or an egg and make it into a sperm or an egg is incredible,' said Mitchell. 'But it does bring the problem of safety. We need to be confident that it's safe before we could ever use those cells to make a baby.' There is also a question over how the technology might be applied. A central motivation is to help those with infertility, but Hayashi said he is ambivalent about the technology's application to allow much older women or same-sex couples to have biological children – in part, due to the potentially greater associated safety risks. However, if society were broadly in favour, he would not oppose such applications, he said. 'Of course, although I made a [mouse] baby from two dads, that is actually not natural,' he said. 'So I would say that the if the science brings outcomes that are not natural, we should be very, very careful.' Unibabies (with sperm and egg made from a single parent) or multiplex babies (with genetic contributions from more than two parents) would also be theoretically possible. 'Would anyone want to try these two options?' said Prof Hank Greely, who researches law and bioethics at Stanford University. 'I don't see why but it's a big world with lots of crazy people in it, some of whom are rich.' Others are ready to contemplate some of the more radical possibilities for the technology, such as mass-screening of embryos or genetically editing the stem cells used to create babies. 'It's true those are possibilities for this technology,' said Krisiloff, adding that appropriate regulations and ethical considerations would be important. 'I personally believe doing things that can reduce the chance of disease for future generations would be a good thing when there are clear diseases that can be prevented, but it's important to not get carried away.'
The Guardian
05-07-2025
- Science
- The Guardian
Lab-grown sperm and eggs just a few years away, scientists say
Scientists are just a few years from creating viable human sex cells in the lab, according to an internationally renowned pioneer of the field, who says the advance could open up biology-defying possibilities for reproduction. Speaking to the Guardian, Prof Katsuhiko Hayashi, a developmental geneticist at the University of Osaka, said rapid progress is being made towards being able to transform adult skin or blood cells into eggs and sperm, a feat of genetic conjury known as in-vitro gametogenesis (IVG). His own lab is about seven years away from the milestone, he predicts. Other frontrunners include a team at the University of Kyoto and a California-based startup, Conception Biosciences, whose Silicon Valley backers include the OpenAI founder, Sam Altman and whose CEO told the Guardian that growing eggs in the lab 'might be the best tool we have to reverse population decline' and could pave the way for human gene editing. 'I feel a bit of pressure. It feels like being in a race,' said Hayashi, speaking before his talk at the European Society of Human Reproduction and Embryology's (ESHRE) annual meeting in Paris this week. 'On the other hand, I always try to persuade myself to keep to a scientific sense of value.' If shown to be safe, IVG could pave the way for anyone – regardless of fertility or age – to have biological children. And given that Hayashi's lab previously created mice with two biological fathers, theoretically this could extend to same-sex couples. 'We get emails from [fertility] patients, maybe once a week,' said Hayashi. 'Some people say': 'I can come to Japan.' So I feel the demand from people.' Matt Krisiloff, Conception's CEO, told the Guardian that lab-grown eggs 'could be massive in the future'. 'Just the aspect alone of pushing the fertility clock … to potentially allow women to have children at a much older age would be huge,' he said. 'Outside of social policy, in the long term this technology might be the best tool we have to reverse population decline dynamics due to its potential to significantly expand that family planning window.' In a presentation at the ESHRE conference, Hayashi outlined his team's latest advances, including creating primitive mouse sperm cells inside a lab-grown testicle organoid and developing an human ovary organoid, a step on the path to being able to cultivate human eggs. IVG typically begins with genetically reprogramming adult skin or blood cells into stem cells, which have the potential to become any cell type in the body. The stem cells are then coaxed into becoming primordial germ cells, the precursors to eggs and sperm. These are then placed into a lab-grown organoid (itself cultured from stem cells) designed to give out the complex sequence of biological signals required to steer the germ cells on to the developmental path to becoming mature eggs or sperm. Inside the artificial mouse testes, measuring only about 1mm across, Hayashi's team were able to grow spermatocytes, the precursors of sperm cells, at which point the cells died. It is hoped that an updated testicle organoid, with a better oxygen supply, will bring them closer to mature sperm. Hayashi estimated that viable lab-grown human sperm could be about seven years away. Sperm cultivated from female cells would be 'technically challenging, but I don't say it is impossible', he added. Others agreed with Hayashi's predicted timescale. 'People might not realise how quickly the science is moving,' said Prof Rod Mitchell, research lead for male fertility preservation in children with cancer at the University of Edinburgh. 'It's now realistic that we will be looking at eggs or sperm generated from immature cells in the testicle or ovary in five or 10 years' time. I think that is a realistic estimate rather than the standard answer to questions about timescale.' Prof Allan Pacey, a professor of andrology and deputy vice-president of the University of Manchester, agreed: 'I think somebody will crack it. I'm ready for it. Whether society has realised, I don't know.' While several labs have successfully produced baby mice from lab-grown eggs, creating viable human eggs has proved far more technically challenging. But a recent advance in understanding how eggs are held in a dormant state – as they are in the human ovary for more than a decade – could prove crucial. In the race to crack IVG, Hayashi suggested that his former colleague, Prof Mitinori Saitou, based at Kyoto University, or Conception Biosciences, which is entirely focused on producing clinical-grade human eggs, could be in the lead. 'But they [Conception] are really, really secretive,' he said. Krisiloff declined to share specific developments, but said the biotech is 'making really good progress on getting to a full protocol' and that in a best case scenario the technology could be 'in the clinic within five years, but could be longer'. Most believe that years of testing would be required to ensure the lab-grown cells are not carrying dangerous genetic mutations that could be passed on to embryos – and any subsequent generations. Some of the mice born produced using lab-grown cells have had normal lifespans and been fertile. 'We really need to prove that this kind of technology is safe,' said Hayashi. 'This is a big obligation.' In the UK, lab-grown cells would be illegal to use in fertility treatment under current laws and the Human Fertilisation and Embryology Authority is already grappling with how the safety of lab grown eggs and sperm could be ensured and what tests would need to be completed before clinical applications could be considered. 'The idea that you can take a cell that was never supposed to be a sperm or an egg and make it into a sperm or an egg is incredible,' said Mitchell, a member of the HFEA's scientific and clinical advances advisory committee. 'But it does bring the problem of safety. We need to be confident that it's safe before we could ever use those cells to make a baby.' There is also a question over how the technology might be applied. A central motivation is to help those with infertility, but Hayashi said he is ambivalent about the technology's application to allow much older women or same-sex couples to have biological children – in part, due to the potentially greater associated safety risks. However, if society were broadly in favour, he would not oppose such applications, he said. 'Of course, although I made a [mouse] baby from two dads, that is actually not natural,' he said. 'So I would say that the if the science brings outcomes that are not natural, we should be very, very careful.' Unibabies (with sperm and egg made from a single parent) or multiplex babies (with genetic contributions from more than two parents) would also be theoretically possible. 'Would anyone want to try these two options?' said Prof Hank Greely, who researches law and bioethics at Stanford University. 'I don't see why but it's a big world with lots of crazy people in it, some of whom are rich.' Others are ready to contemplate some of the more radical possibilities for the technology, such as mass-screening of embryos or genetically editing the stem cells used to create babies. 'It's true those are possibilities for this technology,' said Krisiloff, adding that appropriate regulations and ethical considerations would be important. 'I personally believe doing things that can reduce the chance of disease for future generations would be a good thing when there are clear diseases that can be prevented, but it's important to not get carried away.'
Yahoo
25-03-2025
- Science
- Yahoo
This Mouse Has Two Biological Dads?!
In a lab in Japan, scientists transformed cells from the tails of male mice into eggs. They fertilized the eggs with ordinary mouse sperm and implanted them in surrogate mouse moms. The experiment was repeated 630 times. Although most of the pregnancies failed, seven healthy mice were born. Each of those seven baby mice had two biological dads. The experiment has staggering implications for the future of human reproduction. Biologist Katsuhiko Hayashi, who led the project, predicts that within a decade, a human skin cell could be used to create a viable human egg. The biotech companies Conception Bio and Gameto are already working on this technology. This would allow same-sex couples to have natural offspring. Perhaps even solo reproduction will be possible, with one man generating both the sperm and the egg. Some conservatives are alarmed. "The global fertility industry seeks to erase women from procreation one manufactured egg at a time," Jordan Boyd wrote at The Federalist. Actually, this technology would be empowering for women who want to have children but can't produce viable eggs—or for older women who have already gone through menopause. Younger women would also benefit. If a piece of skin can be turned into a viable egg, women doing IVF will be saved from daily hormone injections and from needles in their vaginas, both of which are part of the standard retrieval process today. Ben Hurlbut, a bioethicist at Arizona State University, told USA Today that this technology is "a perversion of the sanctity of procreation as a fundamental aspect of human life." It's not a perversion of anything. Procreation is a fundamental aspect of human life—and with this technology, more people would be able to take part. Just ask the 9 percent of men and 11 percent of women of reproductive age in the United States who have experienced fertility problems. Marcy Darnovsky, head of the left-wing Center for Genetics and Society, warned on NPR that this technology could have dystopian consequences, noting that "this could take us into kind of a Gattaca world." Darnovsky was referencing the 1997 sci-fi movie in which a eugenicist state is ruled by people born with genetically enhanced abilities. It's true that this technology could allow parents to test their embryos before implantation and select the traits of their future offspring. But IVF already makes this possible. Today, parents routinely test embryos for heritable conditions and for gender. In the future, they may be able to select for more qualities. And there's nothing wrong with that. As Stanford University bioethicist Hank Greely correctly observes, we should rely on "parental choices to make decisions about how people wish to create families." This follows from the reasonable presumption that parents generally seek to provide the best lives for their kids. The sorry history of eugenics in the U.S., where tens of thousands were forcibly sterilized during the 20th century, should make anyone cautious about government meddling in people's reproductive choices. The ability to turn mouse tails into mouse babies could become the latest technology to give humans more freedom to have the lives they choose with the families of their dreams. This video is based on the essay "What if Men Could Produce Their Own Eggs?," from our February 2024 issue. Photo credits: K. Hardy (CC BY 4.0), National Institute of Arthritis and Musculoskeletal and Skin Diseases NIH (CC BY-NC-SA 2.0), Atdoan0 (CC BY-SA 4.0), Internet Archive Book Images (CC0 1.0), Bada Bing (CC BY-NC-SA 2.0), Peter Hermes Furian, Zurijeta, 7active Studio, Srckomkrit Music credits: "Movements," by Skygaze. Licensed by Artlist. Graphics Producer: Lex Villena Narration: Katherine Mangu-Ward The post This Mouse Has Two Biological Dads?! appeared first on
Yahoo
05-02-2025
- Science
- Yahoo
How to reproduce with two fathers – and no biological mother
At the Third International Summit on Human Genome Editing, held in March 2023 at the Francis Crick Institute in London, Japanese researcher Katsuhiko Hayashi stunned attendees when he explained how he had successfully reproduced mice from two male parents. In effect, Hayashi had developed a complex procedure for turning male pluripotent (meaning embryonic or inducible) stem cells into female stem cells, allowing him to obtain eggs from a male. His surprising findings were published in the journal Nature a few weeks later. Almost two years later, a team of Chinese researchers – led by Zhi-kun Li, Wei Li and Qi Zhou of the Chinese Academy of Sciences – has once again shocked the field of genetics with a similar procedure. However, these scientists found a completely different way of achieving the same result. They produced a baby mouse from two males without maternal biological intervention, beyond needing a female mouse to gestate the embryos generated. Their results were published last month in the journal Cell Stem Cell. This new procedure developed by Li and colleagues combats a mammalian control system called genetic imprinting, which prevents viable mammal embryos from being obtained by combining two gametes of the same sex (two sperm or two eggs). These embryos do not survive naturally, since in mammals every embryo has to derive from a male gamete (sperm) and a female gamete (egg). The reason for this is that some genes are only expressed if they are inherited from the mother, while others have to be inherited from the father. And all of them are essential for survival. The Chinese researchers' highly complex process manages to convert, after numerous steps, a spermatozoa into a cell that behaves like an egg cell. They did this by deactivating the imprinting barrier, which is found at twenty points in the genome, through gene editing with CRISPR tools. This cell (now with the genetic characteristics of an egg) can be combined with another spermatozoa to create a viable mouse embryo. That embryo is gestated by a mouse, and the mice that are born are derived from two sperm, from two fathers, without the genetic involvement of eggs, or a mother. This process is still not without problems. As the study's authors acknowledge, the mice created by this process are not fertile, and can only be reproduced through cloning. Additionally, more than half of the mice born to two fathers either do not survive, die young, fail to mature properly, or fail to reach adulthood. In a previous study from 2018, the same research team had shown that mice born to two mothers were fertile and survived longer than those born to two fathers, all of whom died shortly after birth. In their new study, published last month, the results have improved, though only partially. Though these experimental studies were conducted on mice, they raise the question of whether such procedures could ever safely produce human embryos, and what impact this would have. This is not yet possible, though if it were, it would revolutionise fertility treatments. Male same-sex couples, for instance, could both be the biological parents of their children – one would provide sperm and the other would provide pluripotent stem cells which, following either of the two procedures (that of the Japanese or the Chinese researchers), would produce eggs that could be fertilised in vitro and gestated by a woman through surrogacy. Surrogacy is illegal across much of the EU, but permitted in other countries. Similarly, a female same-sex couple could also have biological children, where one contributes eggs and the other pluripotent stem cells that end up producing sperm. Either of the two women could gestate the resulting embryo, and the children born would be the biological children of both mothers. For the moment, these human applications remain in the realm of science fiction – they are not yet technically possible, and it would be unwise to try to implement them. However, assuming that all these processes will be optimised to the point where we can consider offering them in fertility clinics, I believe it is important to reflect on this. We must ask ourselves, as a society, whether we would be willing to ethically and legally accept these techniques. A version of this article was originally published in Science Media Centre España. Este artículo fue publicado originalmente en The Conversation, un sitio de noticias sin fines de lucro dedicado a compartir ideas de expertos académicos. Lee mas: Geneticists have finally solved the mystery of Garfield's orange coat Why more twins are being born than ever before – even though birthrates are falling How (apparently) identical animals can have different genomes – new research The contents of this publication and the opinions expressed are exclusively those of the author and this document should not be considered to represent an official position of the CSIC nor does it commit the CSIC to any responsibility of any kind.
