Eggcellent Idea: Imagining a World Where Men Produce Their Own Eggs

Japanese researchers announced last year that healthy fertile mice had been born using eggs created from male mice’s tail-tip cells. The male-derived eggs were fertilized with regular sperm, thus producing pups with two fathers. Reproductive biologist Katsuhiko Hayashi, who led the work at Kyushu University, thinks that it will be technically possible to create a viable human egg from a male skin cell within a decade, according to The Guardian.
This achievement builds on earlier work in which another team of Japanese researchers created mouse eggs from tail-tip cells that resulted in the birth of healthy offspring in 2017. Another Japanese research group in 2021 using mouse stem cells created sperm that produced healthy fertile offspring.
Now researchers at private biotech companies like Conception Bio and Gameto are racing to see if they can develop this in vitro gametogenesis (IVG) technology as a way to safely enable post-menopausal women, couples experiencing infertility, and same-sex couples to bear biologically related children. Perhaps even solo reproduction in which single men could produce both sperm and eggs that combined would result in them having biological children in the future.
Bear in mind that only seven healthy mouse pups emerged from the 630 two-dad embryos transferred by the Japanese researchers. So significant technical hurdles must be addressed before IVG can be safely used to give birth to human babies. But some folks object to pursuing human procreation using IVG even after it becomes as safe as conventional and in vitro fertilization (IVF) births.
IVG is “a perversion of the sanctity of procreation as a fundamental aspect of human life,” said Ben Hurlbut, a bioethicist at Arizona State University, in USA Today. He added, “It makes it into an industrial project that responds to and also inspires and cultivates the desires of their future customers.” Marcy Darnovsky, head of the left-wing Center for Genetics and Society, warned on NPRthat IVG “could take us into a kind of Gattaca world.” (She was referencing the 1997 sci-fi movie in which a eugenicist state is ruled by people born with genetically enhanced abilities.) Over at the conservative Federalist, Jordan Boyd asserts that by developing IVG, “the global fertility industry seeks to erase women from procreation one manufactured egg at a time.”
The National Academy of Sciences addresses many of these ethical concerns in its In Vitro-Derived Human Gametes conference proceedings report released in October 2023. That report is summarizing the results of a conference on the topic convened by the NAS in April 2023.
Far from “erasing women,” IVG will instead enable otherwise infertile women to produce as many eggs as they desire without having to endure treatments like ovarian stimulation in the hope of yielding sufficient eggs to succeed at conventional IVF.
Hurlbut is right that many people regard procreation as a “fundamental aspect of human life.” This would be especially true for the 9 percent of men and 11 percent of women of reproductive age in the United States who have experienced fertility problems. Then there are people past conventional reproductive age and same-sex couples who would like to have biologically related children. Far from being an “industrial project,” the rollout of safe IVG would fulfill the desires of these future customers to build their families.
What about Gattaca fears? The report does acknowledge that “combining IVG with polygenic risk screening could revolutionize the ability to select embryos.” Polygenic risk screening (PRS) totes up the genetic variants that increase each embryo’s chances of developing a particular disease or trait. This is similar to the already widely accepted practice of pre-implantation genetic diagnosis during IVF, in which parents test and select embryos in order to avoid deleterious heritable conditions. PRS would increase would-be parents’ ability to select a preferred combination of traits from among many more embryos.
Rather than limit the use of PRS, Stanford University bioethicist Hank Greely suggested that, “in general, it is better to 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 potential progeny. The sorry history of eugenics laws 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, including the use of safe IVG. As University of California, Irvine, law professor Michele Goodwin correctly noted, “Where law has intervened over time in matters of reproduction, it has served to undermine civil liberties and civil rights.”