Making Eggs Without Ovaries
Today, we’re launching Issue 04 with this essay about the future of fertility and in vitro oogenesis — a technology that could soon be used to convert human skin cells into eggs or sperm — by one of its foremost developers. Thanks for reading.
In March 2023, a research team at Osaka University announced an extraordinary achievement: the production of viable eggs using cells taken from male mice.
Building on years of research into stem cells and reproductive development, 1 the researchers, led by Professor Katsuhiko Hayashi, developed a method to induce male stem cells to lose their Y chromosome and duplicate the X chromosome, thus becoming female. From there, researchers took the female cells and grew eggs from them using an elaborate protocol they had initially published in 2016.
For nearly all of human history, there was only one way to make a baby. When a man and a woman love each other very much . . . well, you know the rest. But for many people, the usual method of baby-making doesn’t work. This is especially problematic for biological women, whose ovaries lose the ability over time to release healthy eggs. By age 40, most biological women are no longer able to reproduce. 2 And in recent years, rates of infertility have increased along with the average age of childbearing.
