A team of scientists in China has succeeded in creating healthy mouse pups from a pair of female parents. Does this mean human same-sex couples are closer to being able to create children with genetic material from each parent?
“Our results highlight the factors necessary for crossing same-sex reproduction barriers in mammals,” writes the team, led by senior author Qi Zhou of the Chinese Academy of Sciences.
In the scintillatingly named paper, “Generation of Bimaternal and Bipaternal Mice from Hypomethylated Haploid ESCs with Imprinting Region Deletions,” published yesterday in Cell Stem Cell, they explain how they used stem cells and a gene editing technique called CRISPR—Cas9 to create several healthy mouse pups from the genetic material of two female adult mice. Those pups (all female) then grew into adulthood and were able to reproduce with male mice themselves. The scientists were also able to create live mouse pups from the genetic material of two male adult mice, but they did not survive past infancy.
Don’t ask for this technique at your local fertility clinic quite yet, though. As Scientific American points out, “the team ended up with 29 live mice from 210 embryos—a success rate of roughly 14 percent.” That’s not a great rate. Additionally, the magazine notes, citing other experts in the field, there is still much work to be done to ensure there would be no harm in doing this with humans. And the Chinese team’s efforts were “a technical tour de force,” not easily repeated.
The technique they used involved exposing eggs to chemicals that made them divide as if they were fertilized, and then to extract stem cells that contained only half the usual number of chromosomes. They then used CRISPR to “'[wash] out’ the haploid stem cells’ remaining instructions to act like eggs” and “to coax those same cells to act more like sperm.” They injected these sperm-like cells into another egg to create a bi-maternal embryo, and implanted that into the womb of a third mouse who became a surrogate mother. Scientific American has more details if you want them but, like me, don’t have the background to go delving into the original paper.
Additionally, as Forbes reports, citing Hank Greely, director of the Center for Law and the Biosciences and professor of law at Stanford University, “It would be unlikely that federal funding would be permitted for similar work on human embryos.” And implanting such an embryo in a human “requires FDA-approval and is likely to be a long and difficult journey for anyone who wishes to try to gain it in the future.”
Still, as Greely notes, in vitro fertilization (IVF) once faced similar technical and ethical barriers, and now eight million babies have been created via the technique. (They include my own son.) Who knows where new developments may lead?