An anonymous reader quotes a report from The Guardian: Infertile mice have given birth to healthy pups after having their fertility restored with ovary implants made with a 3D printer. Researchers created the synthetic ovaries by printing porous scaffolds from a gelatin ink and filling them with follicles, the tiny, fluid-holding sacs that contain immature egg cells. In tests on mice that had one ovary surgically removed, scientists found that the implants hooked up to the blood supply within a week and went on to release eggs naturally through the pores built into the gelatin structures. The work marks a step towards making artificial ovaries for young women whose reproductive systems have been damaged by cancer treatments, leaving them infertile or with hormone imbalances that require them to take regular hormone-boosting drugs. Of seven mice that mated after receiving the artificial ovaries, three gave birth to pups that had developed from eggs released by the implants. The mice fed normally on their mother's milk and went on to have healthy litters of their own later in life. Writing in the journal Nature Communications, the scientists describe how they printed layered lattices of gelatin strips to make the ovary implants. The sizes and positions of the holes in the structures were carefully controlled to hold dozens of follicles and allow blood vessels to connect to the implants. Mature eggs were then released from the implants as happens in normal ovulation.