Further development is needed, but this technology could one day be used to help relieve shortages in human organs needed for transplantation. (Image credit: J. Wang et al/Cell Stem Cell 2023.) Scientists have successfully grown a human organ inside another animal for the first time. In a new study, published Thursday (Sept. 7) in the journal Cell Stem Cell , researchers inserted human stem cells into genetically tweaked pig embryos. When these were implanted into surrogate pig mothers, the embryos developed early-stage human kidneys within about 28 days. The research is still in its infancy, but the authors say this...