science
Experimental IVF Produces Five Lambs from Lab-Matured Sheep Eggs
Researchers achieved the first live births in a large animal using lab maturation of immature eggs. One of the resulting sheep later produced two offspring of its own.
Jul 11, 3:35 AM·1m read1 source
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Five sheep have been born using an experimental IVF method that matures immature eggs in the lab, according to findings presented by Helen Picton at the University of Leeds. One of those sheep, a female born in early 2024, later produced two lambs of its own in 2026.
Picton and colleagues collected dozens of follicles from sheep and bathed them in a mix of reproductive hormones, including follicle-stimulating hormone, along with growth factors.
About 60 percent of the follicles developed into mature eggs, and roughly 30 percent of those eggs were fertilized to create embryos. The embryos were implanted into 18 sheep, resulting in the five births. The female lamb born in early 2024 went on to produce two offspring this year.
Four additional lambs were born in 2026. The work marks the first demonstration of the technique in a large animal, following similar results achieved in mice more than 30 years ago. Picton presented the results on 7 July 2026 at the European Society of Human Reproduction and Embryology conference in London.
Standard IVF produces a live birth in around 20 percent of cases. Women are born with hundreds of thousands to more than one million immature eggs. Picton said the approach could one day help women whose ovaries were damaged by cancer treatment, but further studies are needed to determine whether human eggs matured this way can be fertilized.
